Household Wastewater Treatment including Septic Systems
This page was archived in September 2013; see home page for current site status
Household wastewater contains pathogens (disease-causing organisms), high concentrations of nutrients such as phosphorus and nitrogen, and some toxic chemicals. This wastewater must undergo some type of treatment before being released to the environment. Treatment includes physical, chemical, and biological (bacterial) processes.
A septic system is one way to treat wastewater on the property where it is generated. Septic systems and similar technologies are called on-site wastewater treatment systems (OWTS) or decentralized wastewater systems. A septic system can be a cost-effective and convenient solution to wastewater treatment, but it must be regularly inspected and maintained to function properly and prevent contamination of nearby wells, groundwater, and streams.
Research has shown that many homeowners do not understand who has authority over septic systems and how they work. Septic system construction and siting are regulated by New York State and local government. Links to the state and county health departments are provided below. Homeowners are responsible for their own septic system maintenance and repair. Proper maintenance will save money in the long run by preventing a system failure and extending the life of the system.
The 1990 U.S. Census found that 20% of New York homes, about 1.5 million, used septic tanks or similar technologies. This is similar to the national figure from the Census Bureau's 2005 American Housing Survey. Within New York state, rural areas and small communities are more likely to use septic systems, while cities are more likely to use municipal sewer systems.
General Info and Maintenance This section also includes information on subjects covered in later sections; for example, signs of system failure and inspection recommendations are covered in the general publications, as well as those specific sections.
Funding to Help Repair or Replace Failing Systems
Causes and Signs of Septic System Failure
Septic System Additives; Household and RV Chemicals
New York State Dept. of Health Regulations Links to the DOH site; includes information about siting, components, design, and alternative systems.
Septic System Siting, Design, and Components Also see the NYS regulations.
"Alternative" OWTS Septic systems cannot be used in some landscapes, such as steep, rocky land. This section has links about "alternative" systems where neither septic systems nor municipal connections are appropriate, as well as information about new and advanced onsite technologies.
Septic Systems and Drinking Water Wells
Flooding and Freezing Issues related to septic systems are covered here; also see the Emergencies page for other issues.
Municipal Wastewater Treatment and General Wastewater Characteristics The focus of this page is on-site wastewater systems rather than public treatment systems, but we do provide links to some good educational sites about municipal wastewater treatment plants.
Links to other sites about septic systems and wastewater treatment
General Info and Maintenance
Your Septic System folder and inserts (Cornell Cooperative Extension, updated 2013, limited paper copies available by request)
Folder and inserts to print on plain paper (14 pages).
Folder 4 pages to print on plain paper: Function and Maintenance, Daily Care, Records, Contact Info, and References
Insert: Buying or Selling a House with a Septic System
Insert: Building or Remodeling a Home with a Septic System
Insert: Alternative and Advanced On-Site Wastewater Treatment Systems
Insert: Septic System Failure
Insert: Considerations for Shoreline Property Owners
Insert: Water Conservation
Folder files for printing and customizing by local CCE or DOH offices:
Folder: PDFs: Front; Inside Front; Inside Back no Tab; Inside Back with Tab (larger page size); Back.
Folder: Word: Front; Inside Front; Inside Back no Tab; Inside Back with Tab (larger page size); Back.
Inserts: Word: Alternative; Building; Buying; Failure; Shoreline; Conservation
Your Septic System - archive of 2012 revision of folder
Your Septic System - archive of original CCE publication, a folder with overview information and 5 fact sheets inside
Need for Licensed Design Professionals - Residential Onsite Wastewater Treatment Systems - (NYS DOH, 2004)
On-Site Sewage Treatment Systems: Keeping Our Water Clean (VHS, uploaded to YouTube, 1994 but still relevant for basic maintenance steps)
Workshops on septic systems in lakeshore communities in winter-spring 2013 via a grant from the NYS Pollution Prevention Institute to the NYS Water Resources Institute.
A Homeowner's Guide to Septic Systems (U.S. EPA, 2002); Spanish (2005); short summary (for printing on cards to distribute)
Maintaining Your Septic System - A Guide for Homeowners (National Environmental Services Center - National Small Flows Clearinghouse (NSFC) Pipeline Magazine, 2004)
Terminology for Onsite Sewage Treatment Systems (CCE Water Treatment Notes #9, 2005)
Septic Systems - Practical Alternative for Small Communties - has septic system diagrams (NSFC Pipeline Magazine, 2004)
Septic System Information (NSFC)
Septic System Basic Information (U.S. EPA)
Homeowner Septic System Checklist (U.S. EPA)
Septic Systems FAQ (U.S. EPA)
What Happens After the Flush? (U.S. EPA, 1997, reprint from The Family Handyman magazine)
Septic Systems - Operations & Maintenance (NYS DOH)
Septic Tank Module (Consortium of Institutes for Decentralized Wastewater Treatment, University Curriculum Project) - has a nice Dos and Don'ts Sheet at the end
Septic Systems and Their Maintenance (Univ. of Maryland Extension, includes FAQ section)
Handle It: Maintain your septic, protect your health (The Groundwater Foundation)
On-Site Wastewater Treatment (The Groundwater Foundation)
Septic Systems for Waste Water Disposal (American Ground Water Trust)
Operation and Maintenance Tips for Your Septic System (Univ. of Arizona Cooperative Extension)
Septic System Owner's Guide (Univ. of Minnesota Extension)
Understanding Your Septic System (Univ. of Minnesota Extension)
Septic System Operation and Maintenance (Univ. of Minnesota Extension)
Individual Home Sewage Treatment Systems (North Dakota State Univ. - has interesting photos and diagrams, but the dimensions and regulations given may be specific to North Dakota)
Principles of Subsurface Treatment and Dispersal (Northern Arizona Univ.)
Septic Systems and Their Maintenance (North Carolina State Univ. Extension)
What You Can Do To Extend the Life of Your Septic System (Univ. of Rhode Island Cooperative Extension)
Conventional Treatment Systems (Univ. of Rhode Island Cooperative Extension)
Landscaping and Other Activities on Your Property (in terms of septic systems, Oregon State Univ. 2000)
Effects of Earthworms in Drainfields (Agricultural Research Service, 2008)
Improving Septic System Maintenance in Coastal Communities (NSCU Cooperative Extension)
Biomats (Penn State Extension, 2006)
Funding to Help Repair or Replace Failing Systems
USDA Rural Development
USDA Rural Development NY - Housing Repair and Rehabilitation Loans and Grants for well, septic, and other repairs for low-income rural residents PDF summary, updated 2011; program website
USDA Rural Development local offices in New York State
Rural Community Assistance Partnership (RCAP) - Home Repair Loan Fund
Catskill Watershed Corporation - Septic Rehabilitation and Replacement reimbursement program (for residents of the NYC watershed)
Frequently Asked Questions
How often do I need to inspect and pump my septic tank?
Your septic system should be professionally inspected every 1-2 years. This will catch problems early, and will help you know how often the tank must be pumped. Periodic pumping of the septic tank keeps solids from accumulating in the tank, reaching the outflow, and clogging the drainfield. A typical septic tank should be pumped, cleaned, and inspected by a licensed professional about every 3-5 years. The time interval depends on results of the inspections, the size of your septic tank, and your family's water use. With a small septic tank, high water usage, or use of a kitchen sink disposal for food scraps, you will need to pump more often. The approximate number of years between pumping can be estimated using the chart below (modified from Septic Tank Pumping, Penn State Extension, 2004).
| Pumping Interval (years) | ||||||
| Number of People in Household: | ||||||
| Tank Size (gallons) |
1 | 2 | 3 | 4 | 5 | 6 |
| 1000 | 12 | 5.9 | 3.7 | 2.6 | 2.0 | 1.5 |
| 1250 | 16 | 7.5 | 4.8 | 3.4 | 2.6 | 2.0 |
| 1500 | 19 | 9.1 | 5.9 | 4.2 | 3.3 | 2.6 |
| 1750 | 22 | 11 | 6.9 | 5.0 | 3.9 | 3.1 |
| 2000 | 25 | 12 | 8.0 | 5.9 | 4.5 | 3.7 |
What should I add to my septic system? What should I keep out of it?
The main thing that makes septic systems work is living bacteria. Plenty of bacteria will be introduced to the system through wastewater inputs, and they will live on the other components of the wastewater. No additions of bacteria, yeast, enzymes, or products containing them are necessary for the septic system to work properly. Research has shown that additives do not enhance the performance of your septic tank. Some commercial additives can even be harmful to the performance of your septic tank, because they kill the bacteria doing all the hard work. Also see the publication Bacterial Additives and Septic Tanks.
Since your septic system is a living system, you should protect it from chemical toxins. Small amounts of household cleaning products and personal care products are usually not a problem in the septic system. When disposal down the drain is necessary, always flush with water and follow label directions. Do not pour large amounts of household cleaning products and other chemicals down the drain. Contact your local government to find out about hazardous waste disposal options. Instead of dumping unwanted medicines down the toilet, contact local pharmacies to see if they have collection programs.
How does water use affect septic systems?
A large amount of water entering a septic tank in a short time can reduce the settling of solids in the tank or disturb settled material, and may cause solids to enter the drainfield. Water conservation in the home will help the septic system function properly. Use low-flow fixtures and repair leaks. Drainage from roofs and hoses should be diverted away from the septic drainfield. Avoid using a kitchen sink disposal. Many tips are included in the publications on general septic system information and maintenance.
In general, waste from water treatment systems, including water softeners, should not be added to the septic system load. Research is being conducted currently to collect more data about the impact of softeners on septic systems. Current evidence is mixed and often anecdotal. This issue is discussed in more detail in links below.
Where should my septic tank and drainfield be located?
In general, avoid
- drinking water wells and natural water features
- flood zones (waste will contaminate other areas, and the septic components may be damaged)
- steep slopes and quick-draining soils (effluent needs to spend time in the drainfield to break down)
- buildings and property boundaries (in case of repairs and to contain wastewater to your own property)
- areas where tree roots may grow toward and damage the septic system
- areas where vehicles may compact the soil
In New York state, the Department of Health sets regulations for septic system construction. We link to their page in the New York State Regulations section below. The section on "Soil and Site Appraisal" gives layout guidelines.
How should I treat my drainfield (leachfield)?
Effluent flows from the septic tank into perforated pipes or other distribution channels. This area may be called the soil absorption field, drainfield, or leachfield. Know the location of your system. If a map of it was not provided when the house was purchased or the system was installed, have your septic inspector help you draw a map that shows your house, the septic tank, and drainfield.
Prevent tree roots from growing into the drainfield. Grass is the best cover. Do not pave, build, or drive heavy vehicles over the drainfield. Divert gutters, drains, and other sources of runoff away from the drainfield.
How do I know if my drainfield (leachfield) is not working properly?
Signs of a malfunctioning drainfield include:
- Pools of stagnant water above the drainfield
- Water-loving plants growing over your drainfield.
- Drainage problems or sewage backup in toilets and drains.
- Unpleasant odors around the house.
- Algae growing in abundance in nearby ponds.
Also see the section below on septic system failure
Causes and Signs of Septic System Failure
Identifying Failing Septic Systems and Straight Pipe Discharges (North Carolina Dept. of Environmental and Natural Resources, PowerPoint Presentation, has many photos)
Is My Septic System Failing? (Loudon County, VA, Health Department)
Why Do Septic Systems Malfunction? (Ohio State Univ. Extension, 2000)
Why Do Septic Systems Fail? (North Carolina State Univ. Extension, 2005)
How Failing On-Site Systems Can Be Hazardous to Your Health (Massachusetts DEP)
Use of Dyes and Tracers to Confirm Septic System Failures (Penn State Extension, 2005)
Offensive Odors Don't Always Mean Septic System Failure (page 30-31 in Small Flows Quarterly Magazine, Fall 2004)
Pumping and Inspection
Septic Tank Inspection (NSFC, 2004)
Inspections Equal Preventative Care for Onsite Systems (NSFC, 1998)
Drainfield Inspection (Small Flows Quarterly Magazine, 2004)
Septic Tank Pumping (Pennsylvania State Univ. Extension, 2004)
Hiring a Good Septic System Inspector (Univ. of Maryland Extension)
What to Expect During a Septic System First Maintenance Inspection (Univ. of Rhode Island Cooperative Extension)
What to Expect During a Septic System Routine Maintenance Inspection (Univ. of Rhode Island Cooperative Extension)
What to Expect During a Septic System Pump-Out (Univ. of Rhode Island Cooperative Extension)
A Homeowner's Guide to Evaluating Service Contracts (Consortium of Institutes for Decentralized Wastewater Treatment)
Septic System Additives; Household and RV Chemicals
Bacterial Additives and Septic Tanks (CCE Water Bulletin, 1999)
Septic Tank Additives (Small Flows Quarterly Magazine, 2002)
Septic Tank Additives (US EPA)
Septic System Additives (Univ. of Minnesota Extension)
Household Chemicals and Your Septic System (CCE Water Treatment Notes #16, 2004, includes home cleaning products and septic system additives)
Septic Tank Systems and Household Cleaning Products (Soap and Detergent Association, print copies also available from us)
Antibacterial Products in Septic Systems (Univ. of Arizona Cooperative Extension)
The Mystery Behind PPCPs (Small Flows Quarterly Magazine, 2004)
Septic System Cleaners (Univ. of Minnesota Extension)
Household Hazardous Waste Chart (Water Environment Federation, 1987)
Alert for RV, Boat, and Mobile Home Owners and Park Operators About Safe Wastewater Disposal (US EPA)
The Influence of RV Chemicals in Marina or Campground Septic Tanks (CCE Water Bulletin, 2005)
RV Holding-tank Treatments & Deodorizers in Septic Systems (Univ. of Arizona Cooperative Extension)
New York State Department of Health Regulations
The New York State laws that regulate septic systems are contained in
Title 10 - Health Rules and Regulations:
Part 75 - Standards For Individual Water Supply And Individual Sewage Treatment Systems:
Section 75.5 - Standards for Individual Sewage Disposal Systems:
Appendix 75-A - Wastewater Treatment Standards - Individual Household Systems. Sections of this document are listed below. They include a glossary and detailed design specifications for septic system components based on estimated water usage, and where the system components can be installed in the landscape.
- 75-A.1 Introduction (including a glossary)
- 75-A.2 Regulation by other agencies
- 75-A.3 Sewage flows
- 75-A.4 Soil and site appraisal
- 75-A.5 House or building sewer
- 75-A.6 Septic tanks
- 75-A.7 Distribution devices
- 75-A.8 Subsurface treatment
- 75-A.9 Alternative systems
- 75-A.10 Other systems
- 75-A.11 New product/system design interim approval
Septic System Siting, Design, and Components
Quality Control for Homeowners (NSFC, 2007, about installation and contracting, with checklists and glossaries)
Soil Characteristics (NSFC, Small Flows Quarterly Magazine, 2004)
Soil Evaluation Techniques (NSFC, Small Flows Quarterly Magazine, 2002)
Soil Evaluation for Home Septic Systems (Ohio State Univ. Extension, 2004)
Onsite Treatment Options - Matching the System to the Site (Small Flows Quarterly Magazine, 2001, pp. 14-19 of document)
Septic Systems: What You Need To Know When Building or Buying a House (NSFC, Small Flows Quarterly Magazine, 2001)
Landscaping Options for Onsite Systems (NSFC, Small Flows Quarterly Magazine, 2004)
Landscaping Septic Systems (NSFC, Small Flows Quarterly Magazine, 2002)
Roof Drains and Septic Systems (Small Flows Quarterly Magazine, 2004, avoiding excess load to septic systems)
Pretreatment Systems: Septic Tanks (Northern Arizona Univ.)
Septic Tank Module (Consortium of Institutes for Decentralized Wastewater Treatment, University Curriculum Project) - has a nice Dos and Don'ts Sheet at the end
Cesspools and Seepage Pits Compared to Septic Systems (Small Flows Quarterly Magazine, 2005)
Septic Tank Effluent Filters (NSF International, includes link to certified product directory)
Excellent collection of diagrams and photographs of conventional and alternative components (Consortium of Institutes for Decentralized Wastewater Treatment)
NSF Wastewater Product Testing (Small Flows Quarterly Magazine, 2004)
Recommended Upgrades for Your Septic Tank: Access Risers, Effluent Screens, and Two Compartment Tanks (Univ. of Rhode Island Cooperative Extension)
Septic Tank Enhancements (NSFC Pipeline Magazine, 2003)
Grease Traps for Septic Systems (Small Flows Quarterly Magazine, 2002)
Grease Disposal Tips To Help the City's Environment (New York City Department of Environmental Protection, applies more to sewers than septics but the main idea is the same)
Fat-Free Sewers - How to Prevent Fats, Oils, and Greases from Damaging Your Home and the Environment (Water Environment Federation, applies more to sewers than septics but the main idea is the same)
Are you singing the septic blues? - article on and mixed information on the impact of water softeners on septic systems (Water Technology, 2008)
The Problems with High Efficiency Furnaces, Water Softeners and Iron Filters Discharging into Onsite Sewage Treatment Systems (Univ. of Minnesota Extension)
Water Softener Use Raises Questions for System Owners (NSFC Pipeline Magazine, 2001)
Land Application Systems: Conventional Drainfields (Northern Arizona Univ.)
Drainfield Rehabilitation (Small Flows Quarterly Magazine, 2006)
Wastewater Technology Fact Sheets (US EPA) - Some of the technical information may be of interest to homeowners. Technologies that save water reduce the amount of wastewater to be treated. There are more than 25 sheets on conventional septic systems and alternative technologies. Most are also available in Spanish.
Septic System Tank (2000)
Pipe Construction and Materials (2000)
High-Efficiency Toilets (2000)
Aerobic Treatment
Low-Pressure Pipe Systems
Septic System Tanks
Septic Tank Effluent Screens
Septic Tank Leaching Chamber
Septic Tank-Soil Absorption Systems
High-Efficiency Toilets
"Alternative" On-Site Wastewater Treatment Systems
Wastewater Technology Fact Sheets (US EPA) - Some of the technical information may be of interest to homeowners. Technologies that save water reduce the amount of wastewater to be treated. There are more than 25 sheets on conventional septic systems and alternative technologies, including sand filters and wetlands. Most are also available in Spanish.
Aerobic Treatment
Low-Pressure Pipe Systems
Mound Systems
Types of Filters
Composting Toilets (1999)
The Living Machine® (2002)
Environmental Technology Initiative Fact Sheets from NSFC - some are listed below, but there are many additional sheets on various alternative wastewater technologies.
Composting Toilets: Quick Summary Technical Summary (NSFC)
Mound Systems: Quick Summary Technical Summary (NSFC)
Water Efficiency: Quick Summary Technical Summary (NSFC)
Excellent collection of diagrams and photographs of conventional and alternative components (Consortium of Institutes for Decentralized Wastewater Treatment)
Composting Toilets (Small Flows Quarterly Magazine, 2004)
Skaneateles Lake Watershed Composting Toilet Project (Small Flows Quarterly Magazine, 2004)
Ultra-Low Flow Toilets (Small Flows Quarterly Magazine, 2004)
Alternative Toilets: Options for Conservation and Specific Site Conditions (NSFC Pipeline, 2000)
Treatment Technologies (Northern Arizona Univ., includes many sections on alternative treatment technologies)
Advanced Treatment Systems (Univ. of Rhode Island Cooperative Extension)
Aerobic Treatment Module (Consortium of Institutes for Decentralized Wastewater Treatment, University Curriculum Project)
Aerobic Treatment Units - an Alternative to Septic Systems (NSFC Pipeline Magazine, 2005)
Aerobic Treatment Units (Small Flows Quarterly Magazine, 2005)
Alternatives to Gravel Drainfields (NSFC Pipeline Magazine, 2005)
Building Constructed Wetlands (Small Flows Quarterly Magazine, 2004)
Non-Liquid Treatment Systems (Composting Toilets) (NSF International, includes link to certified product directory)
NSF Wastewater Product Testing (Small Flows Quarterly Magazine, 2004)
Septic Systems and Drinking Water Wells
Septic Systems and Source Water Protection (NSFC, 2008)
Groundwater Protection and Your Septic System (NSFC)
Your Well & Septic System (Water Systems Council, 2003)
Wells & Septic Systems (Water Systems Council, 2005)
How To Keep Your Water Well (NSFC Pipeline Magazine, 2002)
USGS Nitrate Study Shows Water Supply Threatened from Residential Septic Systems (2007)
Flooding and Freezing
Septic Systems - What to Do after the Flood (US EPA, 2005), also in Spanish
First Aid for a Flooded Septic System (National Environmental Services Center based at West Virginia Univ.)
Septic Systems: After the Flood (Univ. of Minnesota Extension, 2009)
Freezing Problems and Septic Systems (Univ. of Minnesota Extension, 2005)
Preparing Seasonal Cabin Septic Systems for Winter (Univ. of Minnesota Extension)
Checking Frozen Systems to Prevent Future Freezing Problems (Univ. of Minnesota Extension)
Preventing and Thawing Frozen Pipes (American Red Cross)
Municipal Wastewater Treatment and General Wastewater Characteristics
Basic Wastewater Characteristics (NSFC, Pipeline Magazine, 1997)
Characteristics of Residential Wastewater (Northern Arizona Univ.)
The Fundamental Microbiology of Sewage (Northern Arizona Univ.)
Disinfection for Small Systems (U.S. EPA) - discusses organisms in wastewater
Wastewater Microorganisms (Norwalk Wastewater Equipment Company) microscope photographs and videos of organisms that live in wastewater (and also lakes and ponds). The videos run in Internet Explorer but may not run in Firefox.
Septage Management: Quick Summary Technical Summary (NSFC)
Septic Systems - Practical Alternative for Small Communties - has septic system diagrams (NSFC Pipeline Magazine, 2004)
Essay on Septics vs. Sewer Systems (Small Flows Quarterly Magazine, 2004)
Septage Treatment/Disposal (U.S. EPA, 1999); Spanish - compares septics and municipal systems; has information about what happens to pumped material and wastewater characteristics
Primer for Municipal Wastewater Treatment Systems (US EPA, 2004) - mostly about municipal plants, but has some information on septic and other decentralized systems, and excellent glossaries.
Wastewater Treatment for Youngsters (Metropolitan Council, Twin Cities, Minnesota) - excellent tour of a large wastewater treatment plant
Go With the Flow (Water Environment Federation) - online animation of municipal sewage treatment plant
Aquaventurer: Water and WasteWater in Human History (Water Environment Federation)
Video Tour of Chattanooga, TN, wastewater treatment plant (Chattanooga Times, 2008, scroll to bottom of article)
Links to other sites about septic systems and wastewater treatment
Contact your county health department
U.S. Environmental Protection Agency - Septic Systems main page - Also has sections for State and Local Government Officials, and Industry Professionals, including detailed handbooks.
World Health Organization (part of United Nations)
Fact Sheets on Water Sources, Treatment, Sanitation, and Hygiene
Home*A*Syst - An Environmental Risk-Assessment Guide for the Home - program of many extension systems, based at Univ. of Wisconsin
View Table of Contents and Order a Home*A*Syst Manual (1997) from NRAES
Kansas Home*A*Syst Manual (Kansas State University, 1999, chapter 4 is on septics)
National Environmental Services Center, based at West Virginia Univ.
National Small Flows Clearinghouse - funded by the U.S. EPA, concerned with on-site wastewater treatment
Consortium of Institutes for Decentralized Wastewater Treatment - University Curriculum Project - has chapters on many OWTS issues including alternative/advanced treatment systems