Septic Systems and Source Water Protection

Septic systems, also known as “onlot sewage systems,”  treat and disperse relatively small volumes of wastewater from individual homes or small numbers of homes and commercial buildings. When properly sited, designed, constructed and operated, they pose a minimal threat to drinking water sources.  Septic systems can be a significant source of ground water contamination to both public and private drinking water wells when improperly sited too close to drinking water wells, in areas with poorly draining soils, when they are not maintained over time, or are improperly used or constructed. Septic system regulation is usually a state, county or local responsibility.

Septic System Source Water Protection Management Measures

  • Encourage municipalities to implement a septic system management program to require inspection and pumping of existing septic tanks every three years
  • Educate homeowners in all protection zones about the importance of maintaining their septic systems.
  • Evaluate the need for a septic management ordinance as some municipalities have done in Pennsylvania

Septic Systems in Pennsylvania

It is estimated there are more than 1 million onlot sewage systems in the Commonwealth that serve an estimated 3.7 million residents, out of the total population in Pennsylvania of 12.7 million people.  For residents with onlot sewage systems, it is up to the homeowner to maintain and properly care for the system.

All too often, homeowners do not know enough about how to care for their system properly. If not regularly maintained, raw sewage containing pathogens from septic systems can make its way to rivers, streams and groundwater supplies, and pollute drinking water and the places residents play, paddle and fish.

It is important for drinking water protection programs to evaluate the risk that septic systems pose to local groundwater and surface drinking water sources from poorly functioning septic systems – systems that if left untreated, could lead to contaminated water resources.

Why Is It Important to Manage Septic Systems Near the Sources of Your Drinking Water?

Septic systems can be a significant source of ground water contamination leading to waterborne disease outbreaks and other adverse health effects. The bacteria, protozoa, and viruses found in sanitary wastewater can cause numerous diseases, including gastrointestinal illness, cholera, hepatitis A, and typhoid.

Nitrogen, primarily from urine, feces, food waste, and cleaning compounds, is present in sanitary wastewater. Consumption of nitrates can cause methemoglobinemia (blue baby syndrome) in infants, which reduces the ability of the blood to carry oxygen. If left untreated, methemoglobinemia can be fatal for affected infants. Due to this health risk, a drinking water maximum contaminant level (MCL) of 10 milligrams per liter (mg/l) or parts per million (ppm) has been set for nitrate measured as nitrogen. Even properly functioning conventional septic systems, however, may not remove enough nitrogen to attain this standard in their effluent.

Septic systems can contribute to source water contamination for various reasons, including:

  • improper siting
  • poor design
  • faulty construction and
  • incorrect operation and maintenance.

Siting Septic Systems

Septic systems should be located a safe distance from drinking water sources to avoid potential contamination. Areas with high water tables and shallow impermeable layers should be avoided because there is insufficient unsaturated soil thickness to ensure sufficient treatment. Most jurisdictions have adopted, for septic systems, minimum horizontal setback distances from features such as buildings and drinking water wells and minimum vertical setback distances from impermeable soil layers and the water table. In making siting decisions, local health officials should  evaluate whether soils and receiving waters can absorb the combined effluent loadings from all of the septic systems in the area.

Operation and Maintenance of Septic Systems

Proper operation and maintenance of septic systems is perhaps the most crucial prevention measure to preventing contamination. Inadequate septic system operation and maintenance can lead to failure even when systems are designed and constructed according to regulation. Homeowners associations and tenant associations can play an important role in educating their members about their septic systems. In commercial establishments such as strip malls, management companies can serve a similar role. Septic system owners should continuously monitor the drain field area for signs of failure, including odors, surfacing sewage, and lush vegetation.

The septic tank should be inspected annually to ensure that the internal structures are in good working order and to monitor the scum level. Many septic systems fail due to hydraulic overloading that leads to surface ponding. Reducing wastewater volumes through water conservation is important to extend the life of the drain field. Conservation measures include using water-saving devices, repairing leaky plumbing fixtures, taking shorter showers, and washing only full loads of dishes and laundry. Wastewater from basement sump pumps and water softeners should not be discharged into the septic system to minimize hydraulic load. In addition, surface runoff from driveways, roofs, and patios should be directed away from the drain field.

Signs of Failing Septic Systems

The signs of failing systems should not be ignored.  Failing systems may present a
health risk to drinking water.  Source water protection efforts should include education of homeowners about how to conduct proper maintenance as it will reduce the threat of pathogens reaching water supply sources and potentially save homeowners thousands of dollars in costly repair costs.

Warning Signs of Inadequate or failing septic systems:

  • Wastewater backing up into household drains.
  • Bright green, spongy grass on the drainfield, even during dry weather.
  • Pooling water or muddy soil around the septic system or in the basement.
  • A strong odor around the septic tank and drainfield.

On-Lot Wastewater Disposal Regulations in Pennsylvania

The Pennsylvania Sewage Facilities Act (Act 537) requires local governments to administer a permitting system for the installation of on-lot sewage disposal systems. A certified sewage enforcement officer (SEO) is responsible for evaluating permits in one or several townships on the basis of lot slope and soil characteristics.

The SEO may offer advice on which type of system would work best based on a site’s conditions. The SEO must inspect the completed system before it is covered with soil. Repairing or replacing a septic system requires a permit from the local SEO.

Routine maintenance such as tank pumping and distribution pipe flushing can be done without a permit. Some counties and municipalities in Pennsylvania have created septic system maintenance regulations that require all residents to have their septic tanks pumped at prescribed intervals — every three years, for example.

These regulations are designed to protect local groundwater and surface water from being contaminated by a poorly maintained septic system.

PA DEP can provide more information on all aspects of septic systems. The local sewage enforcement officer or the extension educator in your county will also be able to provide valuable advice.



The National Environmental Services Center (NESC) has three video public service announcements (PSAs) about the importance of septic system maintenance for community water quality. Each PSA runs 30 seconds. The PSAs reflect NESC’s ongoing commitment to effective wastewater treatment and source water protection, and are available for communities and watershed groups to use for free. Presented in a humorous light, each video drives home the message that homeowners are responsible for safe guarding drinking water through proper septic tank operation and maintenance.
NESC encourages communities to use these brief PSAs as part of a public awareness campaign to protect source water.
Download the videos by going to:
Click images to view the 3 videos below.

NESC Septic PSA #1 Lifestyle

NESC Septic PSA #2 Squishy Feet

NESC Septic PSA #3 Das Bloop

















Example brochure of PA public water system about septic system care & maintenance – Reading Area Water Authority

PADEP Onlot System Information

Pennsylvania Regulations for Onlot Septic Systems – Chapter 73 Standards for Onlot Sewage Treatment Facilities

PADEP Fact Sheets

An Examination of Failing Private Septic Systems in Pennsylvania by Rick L. Day, Ph.D., Yuanhong Zhu, Ph. D., Stewart Bruce,
and Amy Franklin –
Pennsylvania State University September 2008

Septic System Installation and Maintenance Information

Penn State Extension Webinars- may be viewed free of charge at any time:

Penn State Extension fact sheets and publications related to on-lot septic system management- click here>>.

Siting, constructing and maintaining an on-lot septic system:
Resources from Penn State Cooperative Extension >>

EPA Septic System Resources

Source Water Protection Practices Bulletin: Managing Septic Systems to Prevent Contamination of Drinking Water (EPA 816-F-01-021)

Information is available to help homeowners understand the function and maintenance of septic systems.

Homeowner’s Guide to Septic Systems (PDF) (19 pp, 2MB)

Short version of the homeowner’s guide (PDF) (2 pp, 797K)

Homeowner Septic System Checklist (PDF) (1 pp, 293K)

Septic System Operation and Maintenance:

Go to PA DEP Resource Website >>

Go to US EPA SepticSmart Website>>

SepticSmart Door Hanger

Print directions: Many cost-effective printing solutions are available online for printing these door hanger files. The above files have been designed to accommodate the unique die-cuts for the doorknob punch out offered by these online solutions.

“Did You Know? Leaks” Postcard

Print directions: Provide these files to a local print shop or a professional printer near you. Create mailing labels, add postage, and you are ready to mail to local homeowners.

“Summer Fun” Postcard

Print directions: Provide these files to a local print shop or a professional printer near you. Create mailing labels, add postage, and you are ready to mail to local homeowners.

Long Homeowners Guide

Print directions: Provide these files to a local print shop or a professional printer near you. This will print as single, double-sided sheets that can be stapled.

Homeowners Rack Brochure

Print directions: Provide these files to a local print shop or a professional printer near you. This brochure is sized to roll-fold and fit easily into standard rack brochure lucite holders. Note: the standard PDF versions can be printed on the 11″ x 17″ (tabloid) paper with the “Short Edge Binding” setting of all in-office printers.

Across the country, local health organizations, governments, environmental groups, and others are stressing the importance of properly maintaining septic systems to homeowners. Although the ecological and health impacts of failing septic systems are felt by everyone in the community, homeowners are ultimately responsible for their systems. Get inspired by these case studies showcasing how organizations have successfully reached this audience.

SepticSmart Quick Links


Looking to Launch a Local Outreach Campaign?

  • Check out the SepticSmart Outreach Toolkit! Government officials, industry professionals, environmental groups, and other local organizations can access ready-to-use educational materials, case studies, and more.

Contact EPA SepticSmart Staff:
Phone: (202) 564-1162

SepticSmart Case Studies

EPA Decentralized Case Studies
Additional case studies and demonstration projects are available on EPA’s main Septic (Onsite/Decentralized) Systems website.

EPA’s Decentralized Wastewater Quick Links

EPA’s main Septic (Onsite/Decentralized) Systems web pages also contain valuable information for state and local officials, industry professionals, and partner organizations.

EPA’s Decentralized Wastewater Management MOU Partnership EPA and 16 partner organizations work together to increase collaboration among EPA, state and local governments, and decentralized system practitioners and providers. Many partners have developed outreach and education materials that promote the partnership’s mission of improving decentralized performance and protecting our nation’s public health and water resources. For more information on the MOU partnership, visit EPA’s Decentralized Partners page.

Pennsylvania Septage Management Association>> Go

Center for Watershed Protection Research Materials on Septic Systems

Swann,C._Influence_of_Septic_Systems_at_the_Watershed_Level (1)- article summarizes research on the potential risk of surface and subsurface pollution from septic systems

EPA’s Public Engagement Home Page

EPA’s Nutrient Pollution Outreach and Education Page – Offers various tools and publications to assist in developing effective communications materials related to nutrient pollution. EPA’s Nonpoint Source Program’s Getting in Step Outreach Series – the Getting in Step Outreach Series is a great place to get started and learn how to develop effective outreach. The series includes:

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