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

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

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.

NEHA Offers Free Accredited Private Well Class for Sanitarians

**Please note: These instructions are outdated. Please follow these instructions instead.**

The Private Well Class, partnering with the National Environmental Health Association (NEHA) and the Rural Community Assistance Partnership (RCAP), is excited to announce that NEHA now offers The Private Well Class as a 10-lesson course on their e-Learning website. Each lesson is available for one Continuing Education (CE) Credit from NEHA for any credential program that accepts NEHA CE Credits. The course is completely free, and each lesson can be taken independently.

Over the last 3+ years that The Private Well Class has been available, many environmental health professionals have contacted us about getting CE Credits for taking the class. Because the class was developed for well owners, there was no mechanism developed to provide CE Credits. We are excited to be able to offer this alternative for the many professionals working with well owners.

How to Access the Course

To access the course, you need to register on the NEHA e-Learning website, following the steps below. If you are already registered for the free NEHA courses, you can skip step 1 and proceed to the login screen.

Step 1. Complete this form to create a username and password for NEHA's free courses.

Step 2. Upon login, visit the FREE EPA, CDC, and FDA Sponsored Courses page (if you were not already directed there). Scroll to the bottom and look for the list of sub-categories and click on "Water Quality".

Step 3. Scroll down to the Private Well Course, WQ1601. Click on that title to get to the course material shown below.

Step 4. For each lesson, view and download the lesson, then take the quiz. You have to get 70% to pass.  Please contact us at info@privatewellclass.org if you have any questions about the course.