Types of Septic Systems

So you need a septic system. Did you know that means you’re going to have to pick a type of system? There’s a wide variety of system types out there, but before diving into the details of every one, the ten in this post (considered the most common by the EPA) are a great place to start.

The type of system best-suited for you will depend on things like your household size, soil type, lot size, surrounding water bodies, and more. Here’s the very basics on both conventional types of septic systems and common alternative systems.

Septic Tank

The septic tank itself is a buried, watertight holding tank built to hold and do light treatment on a household’s wastewater. Solid matter settles to the bottom of the tank while liquids are discharged to treat and disperse in the soil. Read more about the septic tank here >>

Conventional System

The most conventional kinds of systems have a septic tank and a trench or a drainfield for liquids to disperse into. The practice of using gravel or stone for this drainfield goes back decades — the stone filters out larger contaminants and microbes in the soil below further treats the water. These systems have large footprints and won’t suit all residential sites; though they are most commonly installed in single-family homes or small businesses.  

Chamber System

Gravelless systems have begun to replace traditional gravel systems in recent years. There are many forms of gravelless drainfield, and they offer a smaller carbon footprint than a gravel system does. In a common type of gravelless system, chamber systems, a series of chamber pipes carries the wastewater directly from the tank into the soil. These systems are ideal for areas with higher groundwater tables and where the septic usage volume is more variable. Read more about chamber systems >>

Drip Distribution System

This type of system can be used in many kinds of drainfields. The tank discharge is slowly dripped out in a wide reaching array of shallowly-placed lateral pipes. Drip distribution does require electrical power to regulate the timed drip delivery, and therefore require higher costs and more maintenance. Read more about drip distribution >>

Aerobic Treatment Units

ATUs are like a miniature municipal sewage plant. The treatment tank is injected with oxygen to stimulate natural bacterial activity for further treatment., and some can have additional  tanks to perform more disinfection and pathogen reduction processes. These systems work well in smaller lots, poor soil conditions, and areas with a high water table or nearby surface water. Read more about aerobic treatment >>

Mound System

A mound system will require building an artificial sand mound for the wastewater to be pumped into and flow through before reaching the native soil. This works well in places with shallow soil or bedrock and with high water tables. They do require more space and maintenance than the average. Read more about mound systems >>

Recirculating Sand Filter System

This type of system is more expensive than most conventional systems, but performs a high level of nutrient treatment. After leaving the septic tank, the wastewater will flow into a pump tank which pumps it at a low volume through a sand filter contained with PVC or concrete. Then, like a mound system, the water will filter into the native soil. Read more about recirculating sand filters >>

Evapotranspiration System

In this kind of system, the wastewater will never reach the soil or the groundwater. Instead, it evaporates from the drainfield into the air. This is only workable in arid, hot conditions with shallow soil. Read more about evapotranspiration systems >>

Constructed Wetland System

As the name suggests, this type of system imitates the treatment processes of natural wetlands. After leaving the septic tank, pathogens and other nutrients will be filtered from the wastewater by microbes, plants, and other media, before reaching a drainfield. The plants in these systems need to be able to survive in constantly wet conditions. Only artificial wetlands should be used to treat wastewater; real natural wetlands are not a wastewater disposal or treatment option. Read more about constructed wetland systems >>

Cluster/Community System

Essentially, a cluster or community system is a septic system large enough to handle the wastewater of two or more households or buildings. You’re likely to find them in rural subdivisions, and they will be subject to common ownership. Read more about cluster systems >>

More Information:

• Find diagrams of each type of system at EPA Septic.

• Peruse decentralized wastewater technology fact sheets.

• 5 Factors to Consider When Choosing a Septic Tank from Pete’s Outflow Technicians

• 10 Different Types of Septic Systems + How to Choose the Right One from The Original Plumber. See here for additional info on outdated systems and other FAQs.

Inaugural Minnesota Private Well Forum Produces Toolkit, Resources

On Monday, May 8, 2023, the Minnesota Department of Public Health held a free inaugural Minnesota Private Well Forum. With a goal of working together to overcome safe water barriers for Minnesota’s 1.2 million private wells users, the 6-hour Virtual Forum hosted a diverse audience. The Virtual Forum included both Speaker Sessions and Collaboration Sessions and attendees included labs, licensed well contractors, delegated well programs, soil and water conservation districts, counties, well owners, and private well organizations, among others, including the Private Well Class.

The Minnesota Private Well Forum brought together people across Minnesota, and beyond, who care about private well users, and through their shared effort to ensure safe drinking water, the Forum:

• Shared how attendees are empowering private well users to protect their health;
• Gathered perspectives on barriers to well testing and treatment and possible strategies to overcome them; and
• Identified ways communities, organizations, and agencies can collaborate and create a more supportive system for private well users and next steps.

Additionally, through funding provided by the UMN Institute on the Environment and with a partnership between Minnesota Well Owners Organization and the Center for Changing Landscapes, University of Minnesota-Twin Cities, a new Toolkit For Local Governments, “Safe Drinking Water For All Minnesotans” was developed. The Toolkit includes information and resources for well water quality screening clinics, information on groundwater contamination, and study findings based on a 2022 survey of 196 Minnesota well owners in Dakota and Stearns counties.

You can download the Toolkit and additional Resources below:

• Safe Drinking Water For All Minnesotans – A Toolkit For Local Governments
• Links and Resources Presenters Referenced – Minnesota Private Well Forum 2023
  

A Bored Well Drilling Demonstration

On October 20, 2021, the Illinois State Water Survey staff were invited to a bored well drilling demonstration in North Central Illinois. Professor Mike Phillips, from Illinois Valley Community College, invited ISWS staff to view the construction of a new bored well. Reynold’s Well Drilling, Riverton, IL, was contracted to construct the well. Reynold’s Well Drilling only installs large-diameter bored wells, typically 30-40 wells every year. According to the driller onsite, they have been busier in the last 5-6 years. The entire process took 4-5 hours and was estimated to cost around $15,000. Reynolds was contracted to drill the well and a separate contractor, Lutes H2O Well Drilling Inc. was contracted to install the distribution lines to home the following day.

Regarding the existing hand-dug large diameter well on the property, the owner mentioned that the sample from that well was tested in 1999 when the home was purchased. The test results showed that the drinking water was high in coliform bacteria, nitrates, iron, and manganese. In response, the Phillips installed a UV treatment system and water softener. The water hasn’t been tested since the initial test in 1999. The old well is brick lined well and about 23 feet deep. The water yield for the old well was 5 gallons per minute.


Figure 1. Well Cover for Brick Lined Well

Figure 2. A View Down into the Brick Lined Well

Figure 3. Drill Rig, Trailer, and Water Truck

The process began with selection of a location for the new well. They chose a location in the front yard and approximately 15-20 feet from the driveway. The drillers began by setting up their truck over the chosen location. Once in place, they started digging, using a 36-inch dirt bucket that removes 1ft of dirt per pass.

Figure 4. Drill Rig Set up over the Well Location

The digging continued for several passes, and a large mound of dirt accumulated near the new well. Once there was a depth of 16 ft removed, a metal sleeve was placed in the top 16 feet of the new well. The sleeve worked as a guard to prevent the dirt along the sides from caving in, which allowed the drillers to continue to dig deeper.

Figure 5. Drill Cuttings

Figure 6. Metal Sleeve to Prevent Cave In

Figure 7. Metal Sleeve In Place in the Borehole

Figure 8. Water From the Bucket Indicates Saturated Material

Drilling continued until water was evident in the drill cuttings. When the driller determined they were at a sufficient depth, they prepared the well for installation.

The well was constructed from a single length of fiberglass casing. To allow water into the well, thin slits were cut into the bottom section of the well. Centralizers were attached in three places equidistant apart which acted as stabilizers to position well casing upright and center it in the borehole. Water was pumped into the annulus to hold pressure to the sides to prevent caving, while a vertical metal beam was used to hold down the fiberglass well casing, so it didn’t float. Filter sand and gravel placed in the annulus served to both hold the well in place, allow for additional water storage around the well, and to help filter the water in the formation before it can get into the well.

Figure 9. Driller Cutting Slits in the Well Casing

Figure 10. Close Up of the Cut Slits in the Well Casing

Figure 11. Fastening Centralizers and A Lid to Lower the Casing into the Well Borehole

Figure 12. Lowering the Well Casing into the Borehole

Figure 13. Adding Water into the Annulus Around the Well

Figure 14. Adding Sand and Gravel into the Annulus Around the Well

To finish the well, water is pumped from the new well until it runs clear, a cap is added to the fiberglass well screen, a submersible pump is installed, and a 6-inch PVC well casing is installed from the fiberglass well cap to the surface. The sleeve is then removed, and the upper portion of the well bore is filled with clay or concrete. At the end of the drilling process, the total depth of the borehole was 43 ft on the bottom, 13 ft at the top, and the top of the water was reached at 22ft. The well will be able to provide 8 gallons/minute. The last responsibility for the driller is to complete a well log and file it with the county health department.


Figure 15. Developing the Well by Pumping It Until the Water Runs Clear

Figure 16. The Fiberglass Cap and 6-inch PVC Casing that will Extend to the Surface

A Gradual Return to In-Person Outreach for the Illinois State Water Survey

In August and early September, staff from the Illinois State Water Survey participated in both the 2021 Illinois State Fair in Springfield, IL and the 2021 Farm Progress Show in Decatur, IL. At the Illinois State Fair, the ISWS had a booth in the “Conservation World” from August 13-15 and August 20-22. According to the Illinois Department of Agriculture, the 2021 Illinois State Fair saw over 472,000 visitors, making it the second highest attended fair since the department began tracking formal attendance numbers in 2014.

In addition, the ISWS had a booth in the “Partners in Conservation” tent from August 31-September 2 at the Farm Progress Show. The Farm Progress Show is the nation’s largest outdoor farm event and attendees and included producers from 46 states and around the world. ISWS estimated to have directly helped at least 278 private well owners at the Illinois State Fair over 6 days and at least 230 private well owners at the Farm Progress Show over 3 days, with many signing up for the Private Well Class.

The Private Well Class program is a free, grant-funded program that provides education and outreach, both online and in-person, to boost knowledge and competency of well owners as well as the thousands of dedicated environmental health, cooperative extension, and water well professionals that serve well owners every day.

Staff not only discussed the water cycle and the role that groundwater has in it, but also had an interactive sand tank flow model that demonstrates how groundwater moves in an aquifer and how contamination can affect private wells using colored dye. The display included a working hand pump for kids to try, which demonstrated how everyone in the “good old days” got water from a well. Private well owners in attendance also had the opportunity to chat with our Privatewellclass.org staff and experts. Information was provided on how to sign up for the free 10-lesson Private Well Class, how to get your well water tested, and where to find other resources available for well owners who want to learn more about how to properly care for their well.

A Time of Virtual Transition for Penn State Extension

It’s no doubt that COVID-19 has forced many organizations to adapt, and this was true for Penn State Extension and their robust private well training program. Bryan Swistock, Water Resources Coordinator and Senior Extension Associate, has received more than 1300 registrations for a recent Water Webinar Series.

Traditionally, Penn State Extension has done in-person “Safe Drinking Water Clinic” workshops throughout Pennsylvania, but many workshops were cancelled when COVID-19 restrictions started in March. According to Swistock, the lack of the in-person option was a major challenge for the program. 

When asked about what Penn State did to solve this problem, he said, ”We decided to try our first webinar in mid-April and were surprised when 240 folks registered.  We did have somewhat of an advantage because our Extension system had been migrating to more online content for several years and had created topic-based email lists. So, we were able to advertise the webinar to people who had expressed an interest in private drinking water content.”

Given the success of the first webinar in April, Swistock and his team decided to follow up with a series of eight weekly webinars on specific private water issues. The topics, dates, and attendance numbers are listed below:

The series was ultimately successful and another series of eight webinars is planned for this fall on different topics.

As far as obstacles go, there has been a separate challenge for some of Penn State Extension’s grant-funded programming.  For those workshops, free water testing has always been provided, which is paid by the grant.  In order to maintain water testing with webinars, Swistock’s team has experimented with sending water test kits to webinar attendees with pre-paid return mailing labels. This way, participants can mail the water samples back to their lab via overnight mail (to meet holding times for bacteria, etc.). 

The advantage of this system is reduced travel time and costs, but the disadvantage is that they need to provide two separate webinars; one to teach people about private water supplies and how to collect their sample and a second to help them understand their results. The reduced travel costs from the traditional methods are also offset by the increased postage costs to have samples overnight mailed to the lab. 

While the new webinar series has allowed private well education to continue in Pennsylvania, Swistock acknowledges that this model can miss homeowners who don’t have internet access.

Disaster Preparedness for Septic System Owners

As we continue to encounter extreme weather events in 2019, it’s important for septic system owners to be aware of their role in natural disaster preparation, response, and recovery.  A natural disaster can include anything from a major hurricane, earthquake, wildfire, seasonal flooding, cold weather event, or an unforeseen power outage. During these events, septic system owners can either prevent or encourage drinking water contamination, the spread of disease, injuries, and hefty recovery expenses depending on their response.

A recent webinar by the U.S. Environmental Protection Agency highlighted some great resources septic system owners and sanitarians can use in disaster preparation. One of the best tools was developed by the National Environmental Health Association (NEHA) this year to provide guidance to septic system users before, during, and after a disaster. What’s frequently included in most of these guidelines is to maintain a healthy, leak proof system. Owners should keep documentation of their system components that include photos, a description of the tank location, and who to call for assistance. Before a disaster, users should turn off system power and reduce water use. When a seasonal vacation home is left empty, the septic system should already be prepared for a natural disaster. During the disaster, proceed to follow the emergency and evacuation advice for your area. Correspond with your local health department and have the system inspected before returning to regular use when the emergency has passed.

With roughly 20% of U.S. houses relying on a septic systems, it’s important that owners are educated and aware of how to respond during a natural disaster. Check out NEHA’s guidelines to make sure you’re ready!

Blog contribution was written by Jill Wallitschek

Can you explain reverse osmosis treatment and discuss its limitations and what it is effective at treating?

Question

Can you explain reverse osmosis treatment and discuss its limitations and what it is effective at treating?

Answer

Reverse osmosis is a water treatment process which primarily involves pushing water through a semipermeable membrane to separate pure water molecules from other ions, molecules, and larger particles. It is important to first understand the term “osmosis.” Osmosis is the movement of a solvent (like water) through a semipermeable membrane, from a less concentrated solution to a more concentrated solution. This natural process will continue until concentrations are equal. Pressure can be applied to the more concentrated side of the membrane to stop this flow, and this is called the osmotic pressure. If even more pressure is applied, in excess of the osmotic pressure, the flow is reversed. This technique/process is called reverse-osmosis. See figure 1 (EPA, 1):

Figure 1: osmosis and reverse osmosis visualized

While the membrane material and its interactions with the various components present in the solution is an important factor in determining removal efficiency, you can generally think of an RO membrane as a very fine filter, with the pore size being a primary guiding factor of what can be removed. Of the common membrane filtration technologies (microfiltration, ultrafiltration, nanofiltration, reverse osmosis), reverse-osmosis has the smallest general pore size, approximately 0.0001 micron (CDC, 2). This is small enough to remove most bacteria, viruses, and many common chemical contaminants.

A typical household reverse-osmosis system is shown in Figure 2. Most are point-of-use units meant to fit in small places, like under a sink. These systems typically have other filters (like a sediment filter and a carbon filter) in front of the RO membrane to help protect it and extend its life. They also will have a holding tank and a spout for dispensing the purified water. Some will have a carbon filter after the membrane for final polishing/cleanup. With units that are working properly, we typically expect to see a total dissolved solids removal rate of about 90% or more.

Figure 2: typical reverse-osmosis system (photo by Dan Webb)

Reverse osmosis systems are generally effective at removing (1, 2, 3): 

• Bacteria 
• Viruses 
• Protozoa 
• Total dissolved solids 
• Inorganic ions and salts, like sodium, chloride, copper, chromium, lead, fluoride, aluminum, barium, cadmium, hardness, iron, manganese, nitrate, radium, selenium, sulfate. 

Some may also remove arsenic, chlorine, and organic compounds, but often these can be difficult to remove, depending on various conditions. Most (probably all) systems will have a carbon filter within the unit, and this should help reduce the concentration of chlorine and organic components. It should also be noted that while RO system will remove microorganisms, it is best to use other methods to prevent these before they get to this treatment stage. If living organisms are present and get do get through the membrane, they can cause biological growth later, like in the final carbon filter, if one is present.

The nature of the membrane material, the chemical properties of the target contaminant, and the pH of the water can all affect removal efficiency. Charged species like ions tend to be more easily removed than neutral, uncharged components. For typical groundwater, with a pH of around 7 – 8, and typical reverse osmosis systems, boron can be difficult to remove. Similarly, arsenic can be challenging to remove sometimes, likely due to the nature of the arsenic species in groundwater sources. Arsenic typically occurs in water in two oxidation states: As(III), “arsenic three,” arsenite; and As(V), “arsenic five,” arsenate. Arsenic(III) tends to be present as an uncharged form H₃AsO₃, and is typically more difficult to remove than arsenic(V), which usually exists as H₂AsO₄^- or HAsO₄^2- (both charged species). Some consumers have had good luck improving arsenic removal by adding an oxidation step (like chlorine) ahead of the RO unit. 

To check specific analytes, it may be helpful to check NSF’s list of certified reverse osmosis drinking water treatment systems: http://info.nsf.org/Certified/DWTU/Listings.asp?TradeName=&Standard=058&ProductType=&PlantState=&PlantCountry=&PlantRegion=&submit3=Search&hdModlStd=ModlStd

Reverse osmosis systems produce about 1 gallon of purified water for every 4 gallons of water fed into the system, with the rest diverted to a waste drain. This can vary between units, though, so if this is a concern, it is important to research this ahead of time. 

The end water produced by reverse osmosis should have very low mineralization, with properties similar to distilled water. The pH will be low (can vary, but generally be slightly acidic… around 6 pH units), but because there is very little buffering capacity, this will generally change quickly as it mixes with other solutions or solids, and typically this is not a concern for consumption of RO water. 

As with other water treatment devices, it is important to remember to maintain reverse osmosis systems properly. As mentioned earlier, there will often be filters in place within the unit ahead of the membrane, and many consumers will have other/external treatments devices, first, like water softeners. These treatment steps and filters help to prevent fouling of the membrane, which helps to keep it at peak removal efficiency. Fouling can result from microbial growth/contamination, hardness/mineral precipitation, organic hydrocarbon coating, or particle accumulation on the surface of the membrane. Pre-membrane filters and post-membrane filters, in addition to the membrane itself, should be replaced on a regular basis to keep the unit working properly. Frequency will depend on the water conditions and household use.

References: 

1) US EPA, EPA 815-R-06-009: MEMBRANE FILTRATION GUIDANCE MANUAL 

2) Centers for Disease Control and Prevention: A Guide to Drinking Water Treatment Technologies for Household Use.

3) NSF: Consumer Fact Sheet, What is Reverse Osmosis

FAQ response provided by Daniel Webb, Illinois State Water Survey Chemist / Public Service Laboratory Coordinator, (217) 244-0625, danwebb@illinois.edu

Words of Wisdom from a Well Owner

Many of the private well owners we come into contact with have been on the fence about testing their well water. We recently received an email from a well owner that was willing to share his experience with others to encourage them not to wait as long as he did (13 years!) to have their well water tested. We interviewed Ralph W. from North Carolina to learn more about his experience and the outcome from the perspective of a well owner.

Q: Can you please give me a little bit of bio on your home and private well? How long have you lived in your home?

RW: 13 years.

Q: Did you know there was a private well when you bought it?

RW: Yes.

Q: What were your initial thoughts on the private well?

RW: I grew up with well water and preferred it to the taste of city water, plus it meant not having to pay a water bill.

Q: Did you drink water from your private well while you lived there?

RW: Yes.

Q: When was the first time you tested your well water and what finally made you decide to test your private well?

RW: We had the water tested for bacteria about 12 years ago and the report showed no coliform contamination. In the summer of 2018 we had the water tested by the City of Raleigh Health Department for all of the organic and inorganic tests that they do and subsequently received a phone call telling us to stop drinking the water because it was contaminated with dieldrin. We tested because of urging from the privatewellclass.org website and from my wife. I thought it was going to be a waste of money.

Q: What was your experience with the well testing?

RW: For $225, the city health department sent out a representative who collected and submitted the water samples.

Q: What contaminants did you test the water for?

RW: In addition to retesting for coliform bacteria, tests were run for a wide range of inorganic minerals and an even wider range of possible organic contaminants.

Q: Did the results surprise you?

RW: It shocked us!

Q: What did the test results say after you had your well tested? Did anything surprise you about your test results?

RW: Yes! We learned that the well water was contaminated with 2 ppb of a very toxic pesticide.

Q: What sort of treatment did you have to do after you received the results?

RW: We immediately switched to drinking bottled water until we could be connected to city water which was available on our street.

Q: Did you receive any aid to treat your water?

RW: Yes. A state administered fund paid the entire cost of connecting to city water and closing the well.

Q: What advice would you give to a well owner who might be on the fence about testing their well?

RW: I very much regret not having tested the water sooner.

Testing your well regularly is probably the most important thing a well owner can do to protect their family’s health. We recommend sampling for nitrate and coliform bacteria annually. These constituents are common and provide an indicator that there is likely a pathway into your well from or near the surface. We also suggest contacting your local health agency for advice and additional information on sampling for additional constituents once every 3 -5 years.

Brochures? For Sure!

How do you get your message out? In-person workshops? What about online webinars or social media? Do flyers still work? What about brochures?

Professionals conducting education and outreach activities often wonder if brochures have gone out of style. We, at the Private Well Class, recently launched a campaign to distribute several thousand brochures—and it was a resounding success! This indicates that brochures are not quite yet a way of the past. If you have ever considered a campaign featuring brochures, flyers, or pamphlets, consider what we have learned from our most recent campaign.

We often discuss barriers to reaching well owners, both behaviorally and demographically. Using a combination of online and in-person methods to help educate individual private well owners helps us extend our reach. This year, our staff developed and distributed a Spanish and English version of a brochure for partners to hand out to well owners. The brochure contains information on useful steps that a well owner can take to make sure that their drinking water is actually safe to consume.

In order to reach as many well owners as possible, we ordered and mailed out brochures for partners to distribute, at no cost to them. Extending the network through our partners was a key component of this campaign. By helping one another, both parties benefitted – our partners received free brochures to help well owners in their county, while we were able to extend our universal message of helping well owners be a better steward of their well and water system.

For the first brochure mailing, we mailed out over 31,000 copies of our English and Spanish brochures. In our second brochure mailing, we are planning to send out 21,000 more.

We asked partners who have received the brochures to give us their feedback. Some of the responses were insightful in terms of how the brochures were distributed and why they were so popular among partners:

“Thank you for providing these brochures. We are a small Health Department with limited funding so this enables us to provide quality education to our well owners.” - Toledo, IL

“Thank you so much for providing this resource. It is a great place to start a conversation with a well owner about being a good steward of their drinking water.” - Columbus, OH

“I think this is a fantastic idea for private owners.” - Montesano, WA

“I pass these out to the well owners when I sample their wells. I also hand them out at health fairs and environmental festivals. Very useful information.” - Wyandotte, OK

“We distribute to real estate agents who work closely with property owners on wells.” - Lincoln City, OR

Want brochures to distribute? Have a questions? You can email us at info@privatewellclass.org to be placed on the wait list for our next mailing or to reach us with your inquiry.

Free Class Now Part of NEHA's Updated eLearning Center

More than two years ago we announced the availability of our free class on the National Environmental Health Association's eLearning platform, with 10 pre-approved CEs for environmental health professionals.

NEHA recently switched technology providers and we are excited to share that our class has made the move. Plus, it's now trackable within your NEHA account.

The Private Well Course is a 10-lesson, self-paced version of The Private Well Class, our 10-week email program for well owners. There's no need to wait. You can access everything at once when you log on with NEHA. Here's how you can access this content for free and without being NEHA member:

Step 1. Create a free account or log in to an existing account on the MyNEHA member portal.

Step 2. If you are asked to purchase a membership, press the "Cancel" button. You will be redirected to a dashboard.

Step 3. Click the "Online Store" tab and then the "NEHA Partner Courses" link.

Step 4. Locate "The Private Well Course" and click the "Add to Cart" button.

Step 5. Click the "View Shopping Cart" link in the upper right.

Step 6. Press the "Checkout" button. You will be directed to a confirmation screen.

Step 7. Press the "Place Order" button.

Step 8. Check your email and follow the instructions to access your course at neha.moonami.com using your MyNEHA login credentials.

Note: We are unable to provide support for NEHA login or continuing education issues. If you have any difficulty, you may email sezcurra@neha.org for customer service.