Can A Septic Tank Float?

As crazy as it might sound, the answer is yes: Septic tanks can float out of the ground. Any buried structure will float when empty if it weighs less than the water that displaces it. That means that when installing any sort of septic system in an area with a high water table and/or that is prone to flooding, you must conduct buoyancy tests and determine if the system will remain stable.

Dr. Sara Heger, instructor at the University of Minnesota’s Onsite Sewage Treatment Program, has broken down the calculation to determine tank stability at Onsite Installer. The basic steps are below, but Dr. Heger’s walk-through explains each step in detail and shows example calculations. You will need to know the individual weights of the following: the empty tank, the minimum amount of water and media in the tank, the soil directly above the tank, and the maximum volume of water that is displaced.

Here’s the calculation:

1. Calculate the weight of water displaced by the tank (buoyant force B).
2. Calculate or look up the weight of the tank (WT).
3. Calculate the weight of the water in the tank (WW).
4. Calculate the weight of the soil cover (WS).
5. Evaluation of net forces.

So if your calculations indicate that the tank will float, what do you do then? Thankfully, there are anti-floatation measures that can be added to the system design plans. Perhaps the most basic is to use concrete, which weighs 85 pounds per cubic foot and can be added into the design in a few different ways. Some fiberglass tanks may also have an anti-floatation lip built onto them.

It’s important to consider that any anti-floatation measure will increase stress forces on the tank, so the tanks must be able to withstand the extra force. Read more from Dr. Heger at Onsite Installer on anti-floatation.

If you ever do need to deal with a flooded septic system, whether the tank has emerged from the ground or not, refer here:

• “Faced with a Flooded Septic System?” also from Dr. Heger at Onsite Installer
• “Protecting a Septic System During and After a Flood” at WaterOperator.org
• Contact the Onsite Sewage Treatment Program at UMinn.

Medications & Your Septic System

Can taking some forms of medications harm a septic system? The short answer? Yes. Some chemicals from medications are not completely metabolized in your body and are expelled in your waste. These chemicals can disrupt the biological action in your tank and drainfield causing it to fill with solids more quickly. More solids in your tank means there is a higher risk of solids flowing into the drainfield leading to septic system failure. 

The best way to ensure your septic system stays healthy and functioning is to provide consistent maintenance and inspections. It is also very important not to flush any medications or household chemicals (antibacterial soaps, harsh cleaning chemicals, chlorine bleach, etc.) down your toilet or sinks. Septic tanks and drain fields depend on both anaerobic and aerobic bacteria to break down the organic waste and clean the water as it is released it into the soil for filtration.

Some steps to protect a costly failure and potential replacement are:

• Flush only body waste and toilet paper down the toilet
• Use minimal household chemicals for cleaning
• Avoid or use minimal amounts of chlorine bleach in your washing machine
• Have your tank pumped more frequently if someone in your household is taking chemotherapy or antibiotic medications for an extended period
• When your tank is pumped, ask your pumper to refill it with fresh water to dilute any residual medications
• Take excess and unwanted chemicals, cleaners, and medications to your local household hazardous waste or medication collection program

Businesses on Septic Systems

If a business is in an area that does not have a public sewer system, or, if the business will generate a higher flow of additional wastewater than a sewer system will be able to handle, a commercial septic system will be necessary. This type of system, also called a large-capacity septic system, is defined by the U.S. Environmental Protection Agency as "a septic system that receives solely sanitary waste from either multiple dwellings or a non-residential establishment that has the capacity to serve 20 or more people per day."

The wide variety of facility types that a large-capacity system could service include schools, religious institutions, office and commercial buildings, shopping malls, hotels, restaurants, convenience stores, and more. Unlike residential septic systems or non-residential systems serving fewer than 20 people per day, the EPA does regulate large-capacity systems in order to protect underground drinking water sources.

Fundamentally, though, a septic system on a business property works in fundamentally the same way as a residential system, just on a larger scale. To keep up with the higher volume of wastewater the system will be handling, large systems will require more frequent pumping, maintenance, and service to ensure they operate properly for as long as possible. Business owners managing water use so that the system is not overwhelmed will also help keep the system in good working order.

Again, similarly to residential systems but on a larger scale, the costs of both installation and operating large-capacity systems will vary widely based on the individual factors of the commercial location and performance needs for the system.  

There are some differences to keep in mind for large-capacity systems. While these systems still only handle sanitary waste (so no industrial waste allowed), there are still different types of wastes produced by commercial buildings that their large-capacity septic systems will need to be able to handle. So they’ll need additional design components — such as grease traps in restaurants to keep fats, oils, and greases (the notorious FOG!) from clogging up the plumping — and more specialized maintenance and service.

Multiple types of septic systems can be used for a commercial installation. AAA Pumping Service recommends sand filter systems, pressure distribution systems, evapotranspiration absorption systems, and cluster systems as well-suited for commercial properties. (A cluster system would serve multiple nearby businesses/commercial properties).

Note: Mention of commercial entities who share educational information does not constitute an endorsement.

Additional Reading

• Large-Capacity Septic Systems | U.S. EPA
• Best Septic Systems for Your Commercial Property | AAA Pumping Service
• Five Facts About Commercial Septic Systems | Moon Site & Septic
• Five Things to Know About Commercial Septic Systems | World Construction Today
• “Design Concerns with Restaurants, Convenience Stores, and Commercial Waste” Presentation | Onsite Installer

Protecting a Septic System During and After a Flood

When a home or the area surrounding it floods, the septic system is at risk of becoming waterlogged. This could be from a leak in the lid, rising groundwater that enters into the system, or an over-saturated drainfield that can't properly drain. A flooded septic system may lead to sewage backing up into the home and cause serious problems for the homeowner. 

Septic tanks may not always experience damage just because there is flooding, but any existing leaks in the system will allow floodwater, silt, and debris to enter the system. This presents a big problem since the extra dirt and debris can cause clogging. Extra water entering the septic system can also cause the floating solids to rise up and plug the pipes. The U.S. Environmental Protection Agency has information on what to do after a flood to ensure your septic system is protected. Below we have summarized this information with a list of dos & don'ts:

Septic System Flooding Dos & Dont's

This video provides some additional tips for how to avoid septic tank flooding and what to do if your system does flood:

Following these tips will help septic system homeowners to be prepared in the event of a flood and protect the septic system from further damages. If you need more specific advice or assistance with your septic system, contact your local health department for a list of septic system contractors in your area.

Surprising Facts About Septic Systems

Septic systems treat and dispose of wastewater for locations that public wastewater systems do not service. Many homeowners living with a septic system don't know much about it other than the fact that they have one. If more homeowners learned the ins and outs of their septic systems, they would have the ability to prevent issues before they arise. This article from Dano's Septic (excerpted below) reveals some surprising facts about septic systems.

Every home has a different pumping schedule

• Septic systems must be maintained regularly (at least once every 3-5 years) but the exact frequency depends on some factors like tank size, system age, and usage habits.

You can't flush everything

• Flushing items like pet waste, feminine products, and even floss can interfere with the system's ability to break down waste and create the need for premature pumping of the system.

Drain cleaners can be dangerous

• Chemical drain cleaners can mess with the balance of your septic tank and create problems down the road. Avoid this "quick fix" whenever possible and call a professional to help unclog any drains.

The system involves much more than just the toilet and tank

• Every single sink, tub, and pipe in the home is connected to the septic system. Even the garbage disposal can affect how the system functions, so it is important to pay close attention not only to what is being flushed down the toilet, but also what is poured down the drain.

Your system can affect the groundwater

• Septic systems have the potential to contaminate the groundwater since whatever enters the septic tank will eventually reach the drain field and seep into the ground.

Drain fields can flood

• This is one of the biggest concerns related to septic systems. When the drain field floods, it quickly contaminates the property with wastewater. Try to practice water conservation as often as possible and schedule a professional inspection annually to prevent this.

Maintaining your system will extend its lifespan

• Septic tanks can last for decades with consistent upkeep but eventually they will need to be replaced. Prioritize repairs and maintenance for the septic system to ensure the longest lifespan possible.

Who Is NOWRA and What Do They Do?

The National Onsite Wastewater Recycling Association (NOWRA) is the premier non-profit organization in the United States that is dedicated to advancing the onsite and decentralized wastewater industry. All types of related professions are represented in membership; including installers, regulators, manufacturers, suppliers, educators, and more.

The association has been advocating for sound practices, public awareness, and solutions to challenges for the onsite and decentralized industry since its founding in 1992. NOWRA’s national headquarters are located in Westford, Massachusetts, though a number of state-level affiliates can be found throughout the U.S. and Canada.

NOWRA’s official mission statement is:

• To strengthen and promote the onsite and decentralized wastewater industry through activities that support recognition and promotion of professionalism for industry practitioners.
• To implement best management practices throughout the industry that provide sustainable wastewater infrastructure solutions.
• To achieve greater public awareness of the economic, environmental, and public health benefits of onsite and decentralized facilities.
• To serve the public interest.

This mission’s execution is guided by a Strategic Framework for Unsewered Wastewater Infrastructure. The principal goal of this framework is to achieve sustainable development and protect both human health and environmental quality. Click here to read more about the framework and its seven components.

NOWRA’s website has a number of resources available for members, including a news & publications page, a documents library, an events calendar with national & state-level events, and a signup form for the group’s email newsletter. You can locate septic system professionals through the Septic Locator tool; all NOWRA members are automatically listed to the locator database.

Perhaps most importantly, NOWRA has a wealth of educational courses available to register for on its website. NOWRA’s “Installer Academy” ensures that all industry professionals can access quality training. Courses are available both in self-paced online formats or in-person through trainings arranged with NOWRA’s expert instructors. The popular online courses include “NOWRA A-Z,” an overview of onsite wastewater treatment; “NOWRA Installer Training,” an overview of installation for both new and experienced installers; “NOWRA Troubleshooting,” an overview of the typical treatment process; and “NOWRA Design,” a framework for designing decentralized systems.

NOWRA online courses can be purchased by both members and non-members, but are available to members at a discount. You can find which states have pre-approved NOWRA’s courses for continuing education credits at this page.

The association also has a number of resources available for community education. Decentralized wastewater systems and the advantages they provide are often poorly understood. A long list of resources explaining the benefits, details, and funding of onsite and decentralized systems may be found here — including resources from NOWRA itself, as well as the Environmental Protection Agency and National Environmental Services Center.

Each year, NOWRA holds an onsite wastewater mega-conference in conjunction with the National Association of Wastewater Technicians (NAWT) and the State Onsite Regulators Association (SORA). The 2023 event was held in Hampton, Virginia, and papers and presentations from the conference are available to review here. This year’s event will be held from October 20-23, in Spokane, Washington. Registration will open by late spring or early summer.

If you are interested in lobbying, NOWRA is constantly working in Washington, D.C., at the Capitol and the EPA, advocating to make sure there is always a seat at the table for those in the onsite and decentralized wastewater industry when it comes to wastewater policy and funding. There are a variety of ways you can get involved in the advocacy and lobbying arm of NOWRA.

From furthering education to assistance in growing businesses to information and outreach to national advocacy, there are many reasons to become a NOWRA member. To learn how to join the national organization or one of the 23 state-level affiliates, visit this page. Direct NOWRA membership costs $150 per year for industry professionals, $95 per year for industry regulators, and $35 per year for students.

At WaterOperator.org, we currently have 125 NOWRA resources indexed in our documents database. To find them, select "HOST" in the dropdown menu, then choose "National Onsite Wastewater Recycling Association." Once you make that selection, a second dropdown will appear where you can choose "CATEGORY," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

Decentralized Stakeholder Partnership Renewed

In 2005, the Environmental Protection Agency formed a Decentralized Wastewater Partnership with eight initial public and private sector partners, with the goal of improving the overall performance and management of decentralized systems. The partnership’s Memorandum of Understanding (MOU) is renewed every three years with the following five priorities:

• Increase outreach and public education about decentralized wastewater/septic systems.
• Identify and utilize current information about decentralized wastewater/septic system use and performance in the United States.
• Promote advanced decentralized treatment technologies to the wastewater industry and the public.
• Share information on funding options to help communities and homeowners with decentralized wastewater/septic system repair and replacement.
• Address workforce, education, training and research needs related to the decentralized wastewater industry.

The partnership has created more awareness of decentralized issues nationwide through SepticSmart Week and other promotional activities the group has planned. It has also led to more interaction between member organizations, helping to develop more consistency in messaging as well as more cooperation and working relationships, which helps advance the goals of the MOU.

The partnership’s MOU was most recently renewed on December 5, 2023, for the seventh signing. The partner organizations have grown in number from eight to 25 as of the newest MOU. Five organizations joined the partnership for the newest cycle, including the United States Department of Agriculture Rural Development (USDA-RD) and the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (WASH). 

The new MOU “[renews] the commitment of EPA and its partner organizations to work together to encourage proper management of decentralized systems and increase collaboration among EPA, state and local governments, and decentralized system practitioners and providers.” The renewal document can be read and downloaded here.

Decentralized MOU Signatories, December 5, 2023

Accomplishments of the 2020 MOU

The chief accomplishment of the 2020 MOU cycle was the implementation of the “Closing America’s Wastewater Access Gap Community” initiative. A team from the EPA and USDA-RD launched and led the program, with technical assistance provided by the Rural Community Assistance Partnership (RCAP), the National Rural Water Association (NRWA), and the Environmental Finance Center Network (EFCN). The pilot program worked in 11 historically underserved communities from Arizona to North Carolina to tackle wastewater management challenges and protect community health.

2022 marked the 10th anniversary of SepticSmart Week, the annual celebration led by the EPA of septic system management. SepticSmart Week 2022 featured a photo challenge which helped create 800,000 impressions on social media. Community and educational events were held across the country.

Partners also released a host of new educational materials throughout the MOU cycle, including reports, position papers, and fact sheets. Notably, RCAP and the National Onsite Wastewater Recycling Association (NOWRA) released a guidebook and training courses for homeowners with septic systems. The MOU Partnership together updated the online training module “Water Infrastructure and Resiliency Finance Center,” and released a series of reports addressing the decentralized industry’s workforce issues.

Among partner organizations, the National Environmental Health Association (NEHA) assisted the Center for Disease Control and Prevention in developing the Private Water Network, which trains professionals to manage private water sources effectively. The Water Research Foundation (WRF) completed two major research projects on improving decentralized technologies. RCAP completed over 150 technical assistance projects in 45 states and territories; 26 of which were specifically decentralized and onsite projects.

For our part, the team at WaterOperator.org and the Private Well Class has been an active non-member of the MOU Partnership, participating in meetings, calls, and assisting with the SepticSmart Week committee and activities.

Read the full report on the 2020-2023 accomplishments of the MOU Partnership for more details on these and many more accomplishments.

For More from the Decentralized Wastewater Partnership

• Visit the partnership’s EPA landing page, where you can find the MOU agreements from each signing cycle, accomplishment reports from each cycle, and highlighted educational materials.
• Check out the series of webinars the partnership has sponsored since 2010.
• Bookmark the EPA’s homepage for septic/decentralized/onsite systems.

What Is a Cluster System?

According to U.S. EPA: "A cluster (or community) decentralized wastewater treatment system is under some form of common ownership and collects wastewater from two or more dwellings or buildings. It conveys the wastewater to a treatment and dispersal system located on a suitable site near the dwellings or buildings. It is common to find cluster systems in places like rural subdivisions."

Image from U.S. Environmental Protection Agency

Cluster systems transport wastewater from a small number of homes (typically 2-10) via alternative sewers to either a conventional treatment plant or to a pretreatment facility followed by soil absorption of the effluent. Cluster systems can be financially sound, environmentally friendly solutions for small community wastewater problems, where conventional central treatment systems are not practical or affordable and where individual onsite systems are inappropriate because of site or soil limitations. 

The advantages of cluster systems are the lower average cost, flexibility in land use, less complex operation and maintenance for the community, and non-discharging, decentralized wastewater treatment systems can provide an environmentally sound alternative for small or disadvantaged communities.

The main disadvantage of cluster systems is the amount of operation and maintenance needed. While it is typically not complicated, alternative sewers have septic tanks that need to be inspected and pumped and mechanical parts and controls that use electricity. Since cluster systems are located onsite, workers are required to travel to individual homes or businesses. This type of decentralized wastewater system requires more frequent maintenance, which can be costly if anything is malfunctioning. 

Another key thing to keep in mind is that cluster systems require a somewhat complex organizational structure in order to make community decisions like fee collection and continuing education of homeowners about wastewater issues. The cooperation of homeowners using the cluster system is much more important than with municipal systems since smaller systems are less resilient and less tolerant of periodic large flows or larger than normal loadings of household chemicals than in large systems, where these peaks are averaged out over a very large user base.

Winter Maintenance for Septic Tanks

In the winter months, septic tanks are vulnerable to damages caused by lower temperatures and excessive snow. The biggest concerns being snow build up and lack of protection from cold temperatures. If your septic tank is located in an area where vehicles can drive over it, watch out for compacted snow that can push it deeper into the system. Fluid that lingers in poorly installed or deteriorating pipes, plumbing leaks, and long periods without using your septic system can all cause it to freeze. 

Your septic system may suffer damages if you do not provide adequate cover like an insulating cover/ blanket. These will help to trap heat inside the system and prevent it from freezing inside. Other ways to help prevent your septic system from freezing are to regularly pump your system (every 3-5 years) before winter, don't dispose of inappropriate waste down toilets or drains, use insulated pipes, and remove trees or plants with strong root systems from on top of your septic system to prevent root interference with the system.

Things to keep in mind when working in extreme cold:

• Wind Speed: high wind speeds can create a wind chill effect which makes it feel a lot colder than the reported temperature states.
• Humidity: humidity will cause heat to be conducted from the body much faster than if you are working in dry air. 
• Hypothermia: without proper protection, hypothermia can become a concern when the air temperature drops below -23 degrees Fahrenheit.
• Frostbite: exposed skin can freeze in 5-10 minutes when temperatures reach -40 degrees Fahrenheit.
• Ice & Snow: ice can freeze your equipment and the weight of snow can collapse structures you may be working in or under.

Always bring extra clothing and try to find a place to warm up when working in extremely frigid conditions. Be sure to remove excess snow from work areas and store your equipment under tarps or in heated areas.

Developing a Septic System Owner's Guide

The Community Septic Owner's Guide online tool is designed to develop an Owner's Guide for everything from a single-family home, a commercial property, or even a cluster system serving 50+ homes. It was funded by the USDA National Institute of Food and Agriculture and created by the University of Minnesota. Some key things to keep in mind about this tool are:

• You will need to register if you are using the tool for the first time
• It contains generic stock/boiler plate general information, system component descriptions and images, and operations and maintenance (O&M) recommendations
• It allows you to upload site specific descriptions, images, and O&M recommendations
• It will produce a PDF guide for your home or structure to be used electronically or printed out
• It allows you to start and stop a project during the process and update it years later when things change
• It does NOT cover every scenario that exists across the US, but the creators of the tool hope it covers a vast majority of them