Frequent Questions on Septic Systems

Septic system inspector with drainfield

Select from the list below to view frequent questions in each category:

About Septic Systems

  • How do I find a copy of my septic system's design?
    • Typically, a septic system is permitted and inspected by your local permitting authority (i.e., local health or environmental department). You can contact these entities to obtain a copy of your property’s septic record drawing (the “as-built” design) and copies of the permit(s). The permit(s) may also have additional information on your system, such as the date of installation, soil properties, etc.
  • How do I know if I have a septic system?
    • One way to determine if your home has a septic system is to check your property records. The property deed, building permit and design plans for your home and property will likely contain information about the presence (or lack) of a septic system. In some cases, there may be visual signs you have a septic system. For example, for some septic systems a mound or small hill is created for the installation of the drainfield. Also, if you follow the plumbing outlet leaving your home, you might find an access riser (black or green disc) or probe for the top of the septic tank. It is usually about 10 feet away from the building.
    • If you have a septic system, you will see a $0.00 charge for wastewater or sewer services on your utility bill (or you will not receive a utility bill). Your home's location also can help you figure out if you have a septic system. If you live in a rural area, there is a high likelihood your home is served by a septic system. You can also talk to your neighbors. If they all have septic systems, your home likely does too. In many cases, people with septic systems also have a private drinking water well instead of public water. If the water line into your home does not have a meter attached to it, that usually indicates you have a private well and not public utility water. You also may not receive a water bill for drinking water if you have a private well.
    • If you are still having trouble, contact your local permitting authority (i.e., local health or environmental department) for a list of local septic system professionals who can help you find your septic tank and drainfield. A septic system professional will walk your property and determine where the system and its components are located.
  • Where should septic tanks be placed?
    • Your local health department may have septic tank placement requirements and a minimum setback distance from your foundation. Typically, it should be located on level ground so solids can settle in the tank. The location of the plumbing outlet usually dictates where the tank is located and depth of the tank to account for adequate slope on the inlet pipe. Septic tanks should be placed away from areas subject to flooding and surface water ponding. The tank should be properly vented. Avoid steep slopes and areas of dense tree roots or other obstructions. Also, place the septic tank where it is accessible for future inspections and pump outs.
  • How close can a septic tank be to a property line?
    • Isolation distances from septic tanks to property lines are typically part of local or state permitting regulations. Contact your local permitting authority (i.e., local health or environmental department) for specific requirements in your area. Your local zoning regulations may also include setbacks to various features like buildings and property lines.
  • How do I get a permit for the repair, new construction, or replacement of a septic system?
    • A septic system permit is issued by your local permitting authority (i.e., local health or environmental department). You can apply for the permit yourself, or the contractor hired to build the system can obtain it on your behalf. Check with your local municipality in the event they also require additional permits to install your system.
  • Is one type of septic system better than another?
    • The type of septic system for your home depends on a variety of factors, such as lot size, ground slope, soil conditions, size of the home/occupancy, local/state regulations, and your budget. Some properties can be served by a conventional gravity septic tank and drainfield, while others may require advanced technologies for wastewater treatment or alternate drainfields – like low pressure pipe or drip distribution systems. For more information on the most common types of septic systems, visit EPA's Types of Septic Systems. Some advanced treatment systems have test results demonstrating their treatment performance. National Science Foundation (NSF) International tests and certifies many wastewater treatment systems. Visit EPA's Advanced Technology for Onsite Treatment of Wastewater, Products Approved by State for links to your state’s approved septic system technologies. 
  • Where can I find a septic system professional to install a new system?
    • Contact your local permitting authority (i.e., local health or environmental department). They typically can assist you with locating a septic system professional in your area.
    • The National Onsite Wastewater Recycling Association (NOWRA) maintains a public database of septic system professionals who are also NOWRA members. Home and property owners can use their Septic Locator tool to find septic system professionals in their area. Many states will license or certify septic system installers. Your local health department can provide additional information on licensed professionals.
  • Where can I find information about septic systems in a specific area?
    • EPA does not have a database of septic systems throughout the U.S. because they are regulated at the state and local level. These data may be tracked on a local basis, depending on the state. Some states maintain a statewide database with information at the county level. For more information, contact the state of interest. Additionally, you can consult the most recent American Housing Survey conducted by the U.S. Census Bureau which has nationwide data available on decentralized system usage. 

Caring for Septic Systems

  • Should I be careful of what I pour down the drain?
    • Yes. Many materials that might be poured down the drain do not easily decompose. This can be harmful to the healthy bacteria that grow in your septic tank and drainfield to help break down organic matter. Do not pour grease (such as fats, butter, wax, cheese, heavy cream), liquid wastes (such as pesticides, drain cleaners, household chemicals, paints, paint thinners), oils or coffee grounds down the drain. If you have a garbage disposal, limit its use because food waste can add an unnecessary amount of solid material to your septic tank. Harmful chemicals put down your drain can also be discharged into the groundwater and can impact drinking water supplies and the environment. EPA's Quick Tip Video explains which items to put or not put down the drain, "Think at the Sink!"
  • Does using a garbage disposal unit impact my septic system?
    • Yes. Using an in-sink garbage disposal unit can impact how often you need to pump your septic tank. Food waste usually is slowly digested by the healthy bacteria in your septic tank and can accumulate as scum and sludge. If a large amount of water enters the septic tank or the tank fills up with solids, it can push the solids into the drainfield, causing the pipes to clog and increasing the thickness of the biomat (a bacteria layer that forms on the bottom and sides of the drainfield trenches). If you must use a garbage disposal unit, your tank will need to be pumped more frequently. 
  • What can I flush down the toilet?
    • Only flush human waste and toilet paper down the toilet.
    • Never flush these items down the toilet because they could clog your septic system and cause a failure:
      • Cooking grease or oil
      • Non-flushable wipes, such as baby wipes or other wet wipes
      • Photographic solutions
      • Feminine hygiene products
      • Condoms
      • Dental floss
      • Diapers
      • Cigarette butts
      • Coffee grounds
      • Cat litter
      • Paper towels
      • Pharmaceuticals
      • Household chemicals like gasoline, oil, pesticides, antifreeze, and paint or paint thinners
    • EPA’s Quick Tip Video explains which items not to put down the toilet, "Don’t Overload the Commode!"
  • Are additives recommended for septic systems?
    • No. Septic tank additives containing bacteria or chemicals are commonly marketed to improve system performance. However, use of these additives is not recommended for domestic wastewater treatment because there is already a significant presence of bacteria, enzymes, yeasts, fungi, and other microorganisms in onsite wastewater treatment systems. Additive products can be ineffective or even harm system operation and the environment. Any operational issues should be assessed by a septic system professional or local regulator. See the septic tank additives fact sheet to learn more: Septic Tank Additives (pdf) (609.27 KB) .
  • Should I avoid driving or building on my drainfield?

    • Yes. Most drainfields (such as rock and pipe, chamber system, etc.) are constructed in open lawn areas and are not designed to handle vehicles or heavy equipment driving on them. The weight of vehicles and heavy equipment compacts the soil, which can damage pipes. Impermeable materials, such as concrete and asphalt, should not be laid on top of a drainfield because they reduce evaporation and the supply of oxygen to the soil. Oxygen is critical to the healthy bacteria in your septic system and the proper breakdown of sewage by soil microorganisms.

    • Do not build any structures in or on your drainfield area without checking with a local designer or permitting authority. It is not recommended to plant trees, shrubs, or vegetable gardens on the drainfield. Tree and shrub roots can ensnarl and damage drainfield pipes. Vegetables can potentially be exposed to sewage effluent and unsafe to consume. Native grasses and ground covers are the most appropriate planting over your drainfield. See EPA's Proper Landscaping On and Around Your Septic System factsheet or WaterSense’s What to Plant for more information. 

    • EPA’s Quick Tip Video explains how to safeguard your drainfield, “Shield Your Field!”

Maintaining Septic Systems

  • Who is responsible for maintaining septic systems?
    • The owner of the system (i.e., the homeowner, property owner, homeowner’s association, or other responsible management entity) is responsible for the overall operation, maintenance, and upkeep of the system, including repairs or replacement. The system users (i.e., occupants, tenants) are responsible for the proper use of the system, such as what materials go down the drain, how much water is used, etc.
    • EPA developed the New Homebuyer's Brochure and Guide to Septic Systems to help new homeowners better understand maintaining their systems.
  • How often should my septic tank be pumped?
    • In general, a septic tank should be inspected every 1 to 3 years and pumped every 3 to 5 years. The frequency of pumping the septic tank depends on the tank size, number of people in the household, habits of water use as well as the amount of solids accumulated in the tank. Some alternative systems that are more complex may require more frequent inspection or pumping. If you are unsure, ask your local septic system professional. A septic tank effluent filter may also require frequent maintenance and should be included in the inspection and maintenance activities. It is important to save your system’s yearly schedule or maintenance records. See the National Onsite Wastewater Recycling Association's Guide and Record Keeping Folder example.
    • Spring is a great time to service your septic system. EPA developed a customizable postcard as a reminder to homeowners on the importance of regular preventative system maintenance.
  • I’ve never pumped my septic tank, is that a problem?
    • If you have not pumped your septic tank in several years, but do not seem to be having any problems, it may mean one of several things:
      • There is minimal water use in the home, and/or the size of the septic tank and the biological activity maintains the solids at sustainable levels. This is rare but may occur when there are only one or two people in the home.
      • The tank has a leak and is discharging wastewater into the ground instead of into the drainfield.
      • The tank is full of solids, which are slowly migrating and may eventually clog the drainfield. This may increase the cost of pumping the tank and may require replacing the entire drainfield if it becomes clogged. 
  • What kind of additives are acceptable for use in my septic system?
    • EPA does not make recommendations on individual septic system products. Commercially available microbiological and enzyme additives are promoted to reduce sludge and scum accumulation in septic tanks. However, these additives are not necessary for a septic system to function properly when treating domestic wastewater. Use caution when using additives in your septic system as they may decrease the performance of septic drainfields, which treat the wastewater from the septic tank. In general, do not use additives made of organic solvents or strong alkali chemicals because they pose a potential threat to soil structure and groundwater.
    • A variety of publications and organizations have assessed the impacts and effectiveness of different kinds of additives. EPA’s Onsite Wastewater Treatment Systems Manual has additional information. Further, some states and localities have state-specific rules and regulations regarding septic system additives. Contact your local permitting authority (i.e., local health or environmental department) for more guidance. 
  • How long does a septic system last?
    • The lifespan of a septic system depends on the material it is made of, the design, installation, service and exposure conditions, and maintenance of the system. Typically, a septic tank made of concrete may last 50 years or more, although older tanks may not be as well constructed as newer tanks. Tanks made from other materials, such as plastic may last a similar timeframe. See the manufacturer for projected lifespan estimates as well as strength, design, installation, and warranty information.
    • If your septic system includes a pump, many pumps and controls will need to be replaced every 10 to 20 years. If you have an advanced treatment unit, check with the manufacturer for estimates of lifespan and warranty information.
    • If your drainfield is more than 25 to 30 years old, the natural biomat that forms in the bottom of the trenches or beds can thicken and reduce the ability of the drainfield to properly discharge the wastewater into the ground. This can cause ponding in the drainfield, surfacing of untreated wastewater, or backing up into the septic tank and into the plumbing in the house.
    • If your septic system is more than 25 to 30 years old, start planning for an upgrade before you are in an emergency situation. It is likely your system is close to its useful lifespan.

Failing Septic Systems

  • How can I prevent a septic system failure?
    • Regular maintenance is the best method to prevent a septic system failure. Septic maintenance includes inspecting the entire system every 1 to 3 years and pumping the tank every 3 to 5 years. The frequency for pumping the septic tank depends on the tank size, number of people in the household, the water habits and use, if a garbage disposal is used, and the amount of solids accumulated in the tank. A rule of thumb is to pump the tank when the solids are two-thirds of the volume in the tank. Routine maintenance is the responsibility of the home or property owner. If you rent a home, you have responsibility for the proper use and operation of the system.
    • In general, you can avoid a septic system failure by:
      • Inspecting your system every 1 to 3 years
      • Pumping the tank every 3 to 5 years or as needed
      • Avoiding excess water use (e.g. spreading out laundry use over the week)
      • Flushing only human waste and toilet paper down the toilet.
  • What are common signs of a failing septic system?
    • Water and sewage from toilets, drains, and sinks backing up into the home’s plumbing
    • Bathtubs, showers, and sinks draining very slowly
    • Gurgling sounds in the plumbing system
    • Standing water or damp spots near or over the septic tank or drainfield
    • Sewage odors around the septic tank or drainfield
    • Bright green, spongy lush grass over the septic tank or drainfield, even during dry weather
    • Straight pipe discharging untreated wastewater to the ground surface
    • Algae blooms in nearby lakes or waterbodies
    • High levels of nitrates or coliform bacteria in surface waters or drinking water wells
  • If I smell a foul odor coming from my septic system, does that mean my system is failing?
    • There may be several reasons for the smell, which can occur inside or outside your home. If you notice an odor, it may be coming from a roof vent or other vent pipe that allows the system pressure to equalize. This is a normal part of your system. Sometimes these vents can become obstructed and clogged (from leaves, debris, etc.) or the vent pipe can freeze during prolonged cold spells. These situations could cause an odor inside or outside of your home. Another possibility is a down draft (changes to wind pattern) or other location-specific conditions, which can create an odor inside or outside your home. In these cases, the vent may need to be cleaned or raised. There are charcoal filters available for roof vents that may also alleviate the odors.
    • If your drainfield is not working properly, that could be another reason you smell an odor inside your home or around the septic system. Soft, wet, or spongy soil (especially when there have been no significant rainfall events) around your drainfield is a good indication of a system failure. For general information on maintenance of your septic system, consult EPA’s A Homeowners’ Guide to Septic Systems.
    • It is not possible to diagnose the exact cause of an odor remotely. EPA recommends you contact a local septic system service provider and/or plumber to address the issue. 
  • What about a smell from the septic system in my recreational vehicle (RV), boat or mobile home?

Inspecting Septic Systems

  • What should I expect in a typical septic system inspection?
    • Septic system inspections are a vital step in making sure your system is operating properly. Regular inspections ensure you and your family do not get sick due to a leak or other problems with your septic system. Since these wastewater systems are located underground, homeowners may overlook having a septic inspection. Routine inspections help prevent expensive repairs to your system or avoid a sewage backup in your home. In many states, a septic system must be inspected with the transfer of real estate. However, it is not only when you are buying a home that these inspections are needed. Septic system inspections should be done every 1 to 3 years for as long as you own your home.
    • 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, “Protect It and Inspect It!”
    • Contact your local permitting authority (i.e., local health or environmental department) for a list of professional inspectors in your area.

Septic System Regulations

EPA does not regulate single family home septic systems. In most states, local health departments issue construction and operating permits to install septic systems under state laws that govern public health protection and abatement of public nuisances. Some states add water resource protection provisions to their septic system regulations because of the possible impacts from nitrogen and phosphorus.

Under most regulatory programs, the local permitting agency conducts a site assessment to determine whether the soils can provide adequate treatment. These programs ensure that ground water resources will not be threatened, and stipulate appropriate setback distances from buildings, driveways, property lines, and surface waters.

Some states permit alternative systems if conventional soil-based systems are not allowable. Very few permitting agencies conduct regular inspections of septic systems after they are installed.

Regulation of onsite wastewater treatment systems:

Septic System Compliance

  • What should I do if I witnessed a violation of environmental quality/law from the neglect of a septic system?
    • If you have witnessed or are aware of an environmental violation, you can file a complaint with your state or local health department. It is imperative to contact your state or local health department as soon as possible to avoid public and/or environmental health risks. You can also report environmental violations to EPA’s Office of Enforcement and Compliance.
  • What can I do about an abandoned septic system that is no longer in use?
    • A property owner may be required to properly remove the abandoned septic tank or drainfield, depending on your state or county rules and regulations. Other rules may allow a system to be abandoned in place where there is little potential for environmental, health, or safety impacts. Contact your local permitting authority (i.e., local health or environmental department) about regulations regarding when and how to properly handle an abandoned septic system in your area.

Paying for Septic Systems

  • How can I pay for my septic system? Are there grants or loans available to help me pay for the repair or replacement of my septic system or to buy a new one?
    • In addition to EPA, there are national financing programs available through the U.S. Department of Agriculture (USDA), as well as other agencies.
    • EPA
      • Clean Water State Revolving Fund (CWSRF) provides assistance for the repair or replacement of failing decentralized systems. Each state’s CWSRF program is responsible for selecting the projects that receive assistance. You can contact your CWSRF state representative to learn more about the application process and eligibility requirements.
      • Nonpoint Source (NPS) voluntary program provides grants and technical assistance to states, territories, and tribes to address nonpoint sources of pollution, including failing septic systems. Depending on your state’s NPS management program, grants may be available to construct, upgrade, or repair individual septic systems. Please note that individual homeowners are not eligible to directly receive grant assistance through this program, as the grants are typically provided to watershed organizations that are actively implementing watershed-based plans to restore impaired waterbodies.
    • USDA
    • There are additional community financing programs that in certain cases may be used on wastewater infrastructure.
      • U.S. Department of Housing and Urban Development (HUD) provides funds to states through community development block grants. The grants fund various projects, including rehabilitation of residential and nonresidential structures, construction of public facilities, and improvement of water and sewer facilities.
      • U.S. Economic Development Administration (EDA) administers various funding programs to promote collaborative regional innovation, public/private partnerships, national strategic priorities, global competitiveness, and environmentally sustainable development.
Financing Options
  EPA CWSRF EPA NPS USDA Rural Home USDA Single-Family Housing USDA Rural Decentralized HUD EDA
Criteria              
Individuals Over 65 Years Old X   X X X X  
Low-Income Households X   X X X X  
Tribal Nations X X X X X X X
Nongovernmental Organizations and/or Community Banks X X         X
States X X       X X
Local/County Governments X         X X

For additional information, visit EPA's Funding for Septic Systems or Water Finance Clearinghouse. The Clearinghouse is an easily navigable web‐based portal to help communities locate information and resources that will assist them in making informed decisions for their drinking water, wastewater, and stormwater infrastructure needs, which includes septic system financing and assistance.

Environmental / Public Health Impacts from Septic Systems

  • Do septic systems impact water quality?
    • In general, a properly installed, sited and maintained septic system should not adversely affect water quality. In some cases, the design may require advanced treatment to reduce the wastewater strength, impacts of nitrogen contamination, or include disinfection when there are properties in close proximity to surface waters.
    • If the system is failing or is an older system that is discharging directly into the groundwater, the wastewater is not treated to reduce pathogens or nutrient levels. If this discharge is in close proximity to a water body, it may negatively impact water quality.
    • Examples of these impacts may include:
      • Groundwater contamination with pathogens, chemicals or nutrients that affect drinking water wells.
      • Surface waters can be contaminated with pathogens, such as E. coli, chemicals, and nutrients including nitrogen and phosphorus.
        • Pathogens can cause illnesses for recreational swimming areas, even requiring beach closures and hazards to humans and pets. Excess nitrogen and/or phosphorus can cause an overgrowth of blue-green algae or cyanobacteria in a short period of time, triggering algae blooms. The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae eventually die, the oxygen in the water is consumed. This can cause fish and other aquatic organisms to die and create regional “dead zones.”
        • Coastal waters are more sensitive to nitrogen contamination from failing septic systems.
        • Freshwater rivers, lakes, and ponds are more sensitive to phosphorus contamination from failing septic systems.
    • The cumulative impact of failing septic systems that are in close proximity to each other and to a water body in environmentally sensitive areas may need to be addressed at the regional or watershed level.
    • For more information and outreach tools, EPA's Nutrient Pollution Outreach and Education Materials offers various tools and publications to develop effective communications materials related to nutrient pollution.
  • Can failing septic systems affect human health?
    • A failing septic system likely discharges untreated wastewater, which contains pathogens (e.g., E. coli), nutrients and other harmful substances directly into the groundwater or onto the ground and into surface waters.
    • Surfacing untreated wastewater from a failed drainfield is a direct public health hazard to anyone exposed to it. Children and pets can unknowingly be exposed to this hazard which can cause illness. If you or others have been exposed to untreated wastewater, contact your health professional.
    • Straight pipes can discharge untreated wastewater directly into ditches, streams and other water bodies causing a direct public health hazard and also a regional public health hazard to anyone who comes into contact with the untreated wastewater.
    • Drinking water from groundwater wells and from surface water sources can be contaminated by untreated wastewater and require filtration and disinfection to remain potable. Check with your local health department about having your water tested.
    • Excess nitrogen contamination in surface or groundwater supplies can impact drinking water systems requiring special treatment.
    • Chemicals that may be discharged into septic systems can negatively impact water quality and public health in both groundwater and surface water sources, even in very small amounts.
    • EPA’s Quick Tip Video explains how regular water quality testing can protect and safeguard your family’s health, “Keep It Clean!” 

Additional Information: EPA Septic Systems Glossary

Septic Systems

Contact Us About Septic Systems
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on September 12, 2024