Stormwater Runoff

Stormwater runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces and does not percolate into the ground. As the runoff flows over the land or impervious surfaces (i.e. paved streets, parking lots, building rooftops, etc.), it accumulates debris, chemicals, sediment, and other pollutants that could adversely affect water quality if the runoff is discharged untreated. Storm sewers can be connected to sanitary sewers and is treated as wastewater when that is the case, so that when discharged it is better for the environment.

We have 554 resources (and counting) on Stormwater in our Documents Database that provide valuable information on this topic. You can search for documents on wet weather management strategies, how to verify the source of inappropriate discharges to storm drainage systems, how to develop a CSO Long-Term Control Plan, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Stormwater within our database just select "CATEGORY" in the dropdown then choose "Stormwater." Once you make that selection, a second dropdown will appear where you can choose "HOST," “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.

This is part of our A-Z for Operators series.

New Decentralized Wastewater Website Coming Soon!

DecentralizedWastewater.org will be launching soon as a new sister program of WaterOperator.org and PrivateWellClass.org.

Through a partnership of the Illinois State Water Survey and the Rural Community Assistance Partnership, the new website will provide training and technical assistance to wastewater professionals, onsite system owners, and managers of centralized and onsite/decentralized wastewater systems. We will host thousands of wastewater training documents, a calendar of training events, a regular webinar series, and more.

If you are seeking documents and events right away, you can check to see what is currently listed on the WaterOperator.org Documents Library and Event Calendar. Existing decentralized wastewater information will continue to be available on WaterOperator.org.

The program’s newsletter will be sent out monthly, and has launched already. You can sign up for the email list here, and check out the January, February, and March editions.

Please feel free to contact us at info@decentralizedwastewater.org if you have any comments, would like us to find something for you, or have information that will help other onsite/decentralized wastewater operators, installers, inspectors, and owners!

Emerging Contaminants and Your Onsite Wastewater Treatment System

When installed, operated, and maintained correctly, septic systems should not pollute groundwater or cause any danger to the drinking water supply. But the unfortunate fact is that pollutants and contaminants do make their way out of septic systems and into groundwater all the same. And this isn’t always to do with poor installation or maintenance — if a septic owner is putting things down their toilets and drains that aren’t meant to be treated by a septic system, these things become all the more likely to get into the groundwater. This is one of the reasons why making sure everyone knows the Three Ps of septic systems is so important! (That’s pee, poop, and toilet paper, of course).

A 2017 study in the journal Environmental Science & Technology showed that American septic systems are regularly depositing pharmaceuticals, consumer product chemicals, and other hazardous chemicals into the environment. Due to their presence in consumer and industrial products throughout society, such chemicals — often called contaminants of emerging concern or emerging contaminants — find their way into bodies and supplies of water in numerous ways, not just through septic systems. They can not only threaten public health by contaminating a human drinking water supply, but cause environmental problems for ecosystems and organisms as well. For instance, the feminization of male fish and fertility issues in other animals have been strongly linked to emerging contaminants.

This 2017 study suggests that besides emphasizing the need to avoid putting pollutants into a septic system, the best way to protect groundwater from septic contamination is keeping septic systems away from the aquifers and wells that supply drinking water. But, of course, many septic systems already exist in such a range and other solutions for preventing them from discharging too many emerging contaminants are needed.

While any chemical going into a septic system that isn’t one of the Three Ps is a contamination risk and absolutely should not enter a septic tank, some chemicals or contaminants will naturally be more of a cause for alarm than others. Right now, the pollutants society is likely most concerned about at large are PFAS compounds and microplastics, both of which have been found coming out of septic systems.

Though PFAS (Per- and polyfluoroalkyl substances, also commonly known as forever chemicals) have become a high-profile concern in more recent years, PFAS have been one of the most frequently detected compounds in drinking water wells since at least 2016, contamination which has been linked to septic systems.  

For more information on protecting groundwater from failing septic systems and forever chemicals, check out this article on the subject from SCS Engineers.

As for microplastics, the impossibly tiny bits of degraded plastic have been found everywhere from clouds to likely into human brains, and some believe septic tanks are the primary source of microplastics found in underwater drinking water reservoirs. The issue of microplastics in its totality certainly cannot primarily be blamed on septic systems, but figuring out how to decrease their presence in as many sources as possible is critical.

Another consideration with microplastics in septic systems isn’t just the environmental contamination — the buildup of solids in the system can also cause issues for the operation of the system. In fact, a 2015 Pumper Magazine article refers to microplastics as “tiny terrorists” in septic systems.

More to the point, microplastics are a type of solid that “remain[s] suspended are small rough to move readily through the screen and into the soil treatment area. If these solids are small pieces of organic material, they will break down or be consumed in the soil. However, if they are inert particles such as … plastics or other synthetic materials, they will not break down in the soil environment and will plug the soil pores, permanently reducing the ability of the soil to accept septic tank effluent. There is no fix when this happens other than replacement.”

Solutions to protect septic systems and the groundwater reservoirs they feed into from microplastics are hard to come by, short of emphasizing to septic owners the necessity of keeping everything but the Three Ps out of their systems and that they should try to buy fewer products containing microplastics to begin with.

How to Prepare a Septic System for a Large Event

Residential septic systems are designed to accommodate the wastewater from a specific number of people, typically judged by the number of bedrooms in the home. This normally doesn’t represent any issues for the regular residents, but the extra bathroom use necessitated by holding a large party or gathering can pose overload challenges for the septic system.

If a septic system is flooded by the overload of water from party guests in a concentrated timeframe, the overwhelming of the tank and drainfield could lead to sewage backups and flushing untreated effluent into the drainfield. In short, a quite possibly ruined party!

There are steps that homeowners can take to prepare for the impact on the septic system ahead of the party; mostly involving efficient use and management of water ahead of time. These are the steps advised by the septic education program at Michigan State University Extension:

• In the days leading up to the party, minimize the amount of water used for laundry, dishwashers, and showers.
• If the planned cooking is water intensive, do as much food prep and cooking ahead of time as possible.
• Rent a portable bathroom.
• Post bathroom rules to advise guests what can be flushed and other bathroom/septic safety tips.
• Have the septic system inspected and pumped before the party.
• Make sure that other outside sources of water, like eavestroughs or gutters, are routed away from the septic drainfield.

More Advice

• Things to Do to Save Septic System During Holidays | Crews Environmental
• A Guide to Holiday Guests and Septic Systems | West Coast Sanitation
• Why You Need to Prepare Your Septic Tank for the Holidays | A1 Tank Service
• Summer Gatherings and Your Septic System | All-Clear Septic & Wastewater Services

OSHA Requirements for Pumpers

It’s never a bad time for a refresh on the requirements of the Occupational Safety and Health Act (better known as OSHA). The act, passed in 1970, comprises a set of federal standards for workplace safety, but it also allows individual states to submit and operate their own safety plans and requirements. State plans may cover all workers in a state, or may only cover state and local government workers only. It is important to know which category your state falls under.

OSHA state plans covering private and state/local government workplaces:
Alaska, Arizona, California, Hawai’i, Kentucky, Indiana, Iowa, Maryland, Michigan, Minnesota, Nevada, New Mexico, North Carolina, Oregon, Puerto Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, Washington, Wyoming

OSHA state plans covering only state/local government workplaces:
Connecticut, Illinois, Maine, Massachusetts, New Jersey, New York, Virgin Islands

No state plan, follows federal OSHA plans:  
Alabama, American Samoa, Arkansas, Colorado, Delaware, Florida, Georgia, Guam, Idaho, Kansas, Louisiana, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Dakota, Northern Mariana Islands, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Texas, Washington D.C., West Virginia, Wisconsin

State plans often don’t differ drastically from the federal OSHA plan, but the states of California, Michigan, Oregon, and Washington do have plans with substantial differences from the federal one.

Find your state OSHA office here >>

If you are in need of assistance in identifying and/or fixing workplace safety issues, most states do have consultation services available for free as part of the On-Site Consultation Program. Other OSHA programs workplaces can participate in include the Alliance Program, the OSHA Strategic Partnership Program, the Voluntary Protection Programs, and the OSHA Challenge Program.

Read more about the OSHA cooperative programs here >>

Keep in mind that the supervisor or crew leader of an onsite/decentralized wastewater work crew will typically be the OSHA competent person (unless there is a different employee specifically assigned to oversee safety). Whoever is in charge of safety, they must be able to identify critical issues, know and follow OSHA requirements, enforce a written safety plan, and create a culture of safety for the workforce.

The top reasons for accidents include rushing, poor concentration, and simply being in the wrong place at the wrong time. A comprehensive safety plan can help address some of these causes and minimize damages after accidents do occur.

For more:

• A Pumper's Guide to Federal and State OSHA Standards, Pumper Magazine
• Focus on Safety: Installers Need to Make Safety a Priority, Onsite Installer
• Occupational Safety and Health Administration

Septic System Inspection Basics

Inspections are an integral part of making sure that a septic system is operating properly. Homeowners often overlook having a septic inspection done since systems are located underground and out of sight. However, regular inspections help to make sure that everyone in the household is protected from getting sick due to leaks or any other issues from the septic system. A routine inspection schedule will help to prevent the necessity of expensive repairs to the system and to avoid a sewage backup in the home. Septic system inspections should be done every 1 to 3 years for as long as you own your home.

What to expect in a typical septic system inspection? In general, an inspection will involve the following:

• Review of the system permit, design, and installation records (including system age)
• Review of the septic tank pumping and system maintenance records
• Opening and inspecting all tanks (septic tank, pump tank, distribution box)
• Evaluating the septic tank sludge and scum levels and determining the need to pump
• Assessing the condition of the septic tank effluent filter (if installed)
• Looking for signs of leakage, such as low water levels in the tank
• Looking for signs of backup, such as staining in the tank above the outlet pipe
• Evaluating the integrity of the tank, inlet and outlet pipes and looking for signs of corrosion
• Verifying all electrical connections, pumps, controls, and wiring are intact
• Possibly using a camera to look at solid pipes and leach lines for blockages or collapsed piping
• Evaluating the drainfield for signs of system failure, such as standing water (surfacing) or unequal drainage
• Possibly excavating parts of the drainfield to look for signs of ponding in the system or groundwater impacting the drainfield
• Examining the distribution box for structural integrity and to make sure drain lines are receiving equal flow
• Reviewing other available records on water use and required inspections, monitoring, and reporting to ensure system compliance with local regulations regarding function and permit conditions.

EPA’s Quick Tip Video walks through a typical inspection:

How to Abandon a Septic System

There’s a number of situations in which a septic tank/system might need to be abandoned: replacing it with a new system, connecting to a city sewer, or abandoning a property altogether. Septic tanks, cesspools, leaching pits, dry wells, and everything related must be properly cared for and not simply left as they are. Most important is to ensure that access for future discharge from the system will never be possible.

Many states or localities will have specific requirements for procedures on abandoning a septic system. For example, you can take a look at the Minnesota Pollution Control Agency’s guidance on abandoning a sub-surface sewage treatment system, where several state codes are referenced.

According to Sara Heger, septic educator at the University of Minnesota, there are three common practices for what to do with the empty tank:

1. Remove and dispose of the tank at a landfill.
2. Crush the tank entirely and backfill the hole. Water has to be able to drain through it, so it must be completely broken.
3. Fill the tank with a material like concrete that won’t let liquids flow through. There must be no risk of collapse in this scenario.

Basically, you never want to have an abandoned septic tank lying out exposed like in the photo above! Before codes and regulations for old septic systems came into place, it was common practice to simply leave the tanks where they were and forget about them. But this is quite dangerous. Old homes that were hooked into a sewer system long after construction should be inspected for old septic systems when sold.

An improperly abandoned septic system poses several possible risks. They could collapse into sinkholes, spread disease if untreated waste comes into contact with groundwater, or release toxic gasses like methane and hydrogen sulfide.

Be on the lookout for these signs of an abandoned septic system that is leaking, from B&B Pumping in Fort Worth: excessive weed growth on a lawn or algae on a pond, a perpetually soggy patch of lawn, an area of lawn that smells like human waste, unstable and sinking land, or pipes physically protruding from the ground.

Building over the top of even a properly abandoned septic tank isn’t a good idea, since sinking problems or leaked pollution could still occur if the area isn’t handled with care.

Costs of an Onsite Wastewater System

How much does a septic system cost in 2024?

There’s no simple answer — the cost of every single onsite treatment system is going to vary according to a number of factors. What we can tell you is this: as of 2024, HomeAdvisor.com, which aggregates home improvement and maintenance resources, lists the typical range of septic projects to cost between $3,484-$11,703.

The basic factors that HomeAdvisor identifies as driving the cost variations include the size, type, and material you need for the system. Be aware that these three key factors, as well as some others, can drive your costs up well beyond the upper end of that range.

Visit HomeAdvisor for a detailed breakdown of the ranges of costs for tank size, anaerobic vs. aerobic system tanks, types of alternative systems, material types, installation add-on costs, replacement costs, and more.

You can also get an estimate of the costs for your specific project’s needs, by entering information into their estimate tool. For the sake of accuracy and due diligence, it’s recommended to have at least 2-3 cost estimates before determining a final estimated price.

To find other septic professionals in your area, check NOWRA’s Septic Locator lookup tool. You’ll want to be able to list other septic professionals as references for your work, or to check the cost estimates with, when engaging with new potential clients. Networking is important!

So what do you do if you need help financing your septic project? Thankfully, there’s a number of resources available for assistance. You may want to visit the Financing page at the National Onsite Wastewater Recycling Association website — NOWRA has a long list of sites and organizations to visit for assistance, including the Environmental Protection Agency, the Department of Housing and Urban Development and the Department of Agriculture, and more.

Some other resources we would like to particularly recommend:

• The Rural Community Assistance Partnership (RCAP) provides technical assistance and support to rural communities across the country. Their Water and Wastewater Technical Assistance Program has a special focus area in onsite/decentralized wastewater. While RCAP’s national organization does not provide services directly, their regional offices can assist with coordinating help for your community. Contact RCAP here.
• The Financing Septic Systems module in the EPA’s Water Finance Clearinghouse. The module is for homeowners seeking information to support the operations and maintenance, repair, or new construction of septic systems.
• Septic at EPA — Along with a host of other septic-related information and resources, the EPA has funding sources listed by federal programs, individual states, and tribal communities.

Well Water Contamination from Septic Systems

Many homeowners who use a septic system to provide wastewater treatment for their home often get their drinking water from a private well. If the septic system is malfunctioning or happens to be located too close to a drinking water well, contaminants from the wastewater can end up in drinking water. Learn how to locate, operate, and maintain your septic system to protect nearby wells and preserve the groundwater. Your septic system could contaminate your drinking water well or a nearby well under certain conditions, so it is important to regularly test the drinking water from your well (once a year is recommended) and take corrective action as needed.

Water from your toilets, showers, and other appliances contains harmful bacteria, viruses, and nutrients that could make you sick if it were to enter your well without being properly treated first. Maintenance issues like a full or cracked septic tank or a plugged drainfield can cause untreated wastewater to enter the surface water or groundwater. 

According to U.S. EPA: "Filtering wastewater through the soil removes most bacteria and viruses (also known as pathogens) and some nutrients. While soil can treat many contaminants, it cannot remove all of them (e.g., medicines, some cleaning products, other potentially harmful chemicals). If untreated wastewater surfaces in the yard, wastewater may contaminate your drinking water through an unsecured well cap or cracks in the well casing. It’s important to avoid flushing medication and chemicals into your wastewater since it could contaminate your drinking water."

The contamination risk to your well is lower the farther apart the well and septic system are located, the deeper the well is placed (and if it is in bedrock or below a defined layer of silt or clay,) or when your septic system is pumped and serviced on a regular basis.

The contamination risk to your well is higher if the well is at a shallow depth and in permeable soil, if the groundwater flows from the septic system towards the well, if there are many homes on septic systems near the well, or if there is poor construction or maintenance of the well and/or septic system.

Of course, there are a number of factors that can contribute to well contamination, from human mistakes and interference to natural groundwater chemistry. This video from our sister site, PrivateWellClass.org, discusses the basic circumstances that can lead to contaminated well water, and the kinds of naturally occurring contaminants that can be found in private wells.

Prolong the Life of Your Septic System

Regular maintenance and pumping out your septic system will help to prevent costly repairs. However, there are daily precautions that can be taken to help a septic system function properly. 

To flush or not to flush
The only things that should be flushed down the toilet are wastewater and toilet paper. Disposing of sanitary products, paper towels, tissues, diapers, etc. will cause harm to the septic system and you will need more pump-outs.

Don't put food down your sink
Food waste, coffee grounds, fat, and grease will cause great harm to the septic tank. Instead of disposing your food down the sink, try a compost pile for any non-meat food waste.

Don't use a garbage disposal
The garbage disposal doesn't make it easier for the system to handle food, grease, and fat. If you are going to have a garbage disposal, you need to have a larger than normal tank with an effluent screen, and that you pump the system more frequently. 

Don't rinse toxic materials down the sink or toilet
Pouring disinfectants, oils, paint, drain clearing products, etc. down the drain can damage the septic system. If enough toxic material reaches the septic tank, the tank's function can be impaired. 

Reduce your water usage
Cutting back on water protects your septic system by reducing the load of wastewater that the system has to handle. If you repair all leaky faucets and toilets, install low-flow water fixtures, and turn the water off while brushing your teeth or shaving, it will save money on water bills and save your septic system in the long run.

Taking care of your septic system by following these precautions will extend the life of your septic system and reduce the number of costly repairs that need to be made down the line.