Job · Wells and septic
Wells and septic in Fairfax County
Fairfax County's Health Department runs the program for private wells and septic systems; the county code requires a septic tank pump-out at least every five years, and well owners are responsible for their own water's safety.
Revised November 3, 2026 · who makes this map
| Place | What happens there | Turn to |
|---|---|---|
| Fairfax County (unincorporated) | The Health Department's Onsite Sewage and Water Program handles septic and wells through the PLUS portal, on 703-246-2201. This is the only part of the map where we found a program for them. | Sheet 13 |
| DC | DC Water supplies water and sewer, and its pages describe service lines and laterals, not wells or septic tanks. Unless your records say otherwise, assume public service. | Sheet 1 |
| Arlington | The county supplies water and its own sewer pages describe mains and laterals. We found nothing on wells or septic; if your records show one, ask the county. | Sheet 6 |
| Alexandria | The city maintains sanitary, storm and combined sewers. We found nothing on wells or septic. | Sheet 8 |
| Falls Church, Vienna, Herndon, City of Fairfax | Their pages describe public water and sewer. Wells or septic are not confirmed and, if a record shows one, are likely a matter for the county Health Department; ask. | Sheet 14 |
Why only Fairfax County
Private wells and septic systems matter in the parts of Fairfax County where public water or sewer is not available. In DC and the inner suburbs, every source we found describes public service, so a well or a septic tank would be an exception. We cannot rule one out for a given house. Check your records before assuming.
What the county's Health Department says about septic
Septic systems, which the county calls onsite sewage systems, are described as a safe way to dispose of wastewater when properly designed, installed and maintained. Failures happen because of poor design, poor maintenance, or because the system has reached the end of its life. A failing system can discharge untreated sewage onto neighboring yards or into creeks or ditches, which the page says is a health risk to people, pets and the environment.
Chapter 68.1 of the county code says systems that do not need a state discharge permit must have the tank pumped at least once every five years. An unknown or older pump date is the page's cue to book one. Contractors enter pump-out details in PLUS. Alternative systems have separate inspection and sampling rules, with an operator, within 180 days of approval and annually after.
Wells
The county says a private well is an adequate alternative to a public supply when installed properly. A permit to build one comes through a PLUS application under Chapter 70.1, the Private Well Water Ordinance. If your water comes from a well, the page says you are responsible for its safety. Homeowners should have the water tested every year for bacteria and chemical contaminants, and again if the smell, taste or appearance changes, or if land use around the property changes.
If the county tells you a sample is unsatisfactory, it recommends disinfection, by a well contractor from its list or by following its published guidelines. That procedure uses very strong chlorine, so we do not repeat it here; ask the Health Department or a licensed well contractor. Geothermal wells need a Health Department permit and a licensed well water supply provider.
Testing water
Bacteria and chemical contaminants don't show on a hardness, iron and pH kit. Use a certified lab for those, and the county's program is the place for official sampling.
For hardness, iron and pH only, not bacteria or chemicals, one option is a hardness, iron and pH field test kit at Quality Water Treatment (that store has the same owners as this map).
If a lab test shows hard well water, one option to compare is: a well-water softener at SoftPro (that store has the same owners as this map).
Digging and permits
Tank and drain-field work is for licensed contractors, with 811 called first. County staff will not probe or auger a site sooner than three working days after a request, to allow for utility clearance. See digging and 811. For where a house sits among the water and sewer rules, see who owns which pipe and sewer lateral repair; for the county's permits, permits by place.
Backups
If sewage appears indoors, stop using drains, keep clear of it, and keep people and pets away. With septic, call a licensed septic contractor. For a public sewer house, call the utility. See basement backups.
Check your own address
- Find out whether your house has public water and sewer: check the water bill and tax record before assuming either way.
- If you have septic, find the date of the last pump-out; the county's page shows how to check it.
- Ask the Health Department on 703-246-2201 about testing and about contractors for pump-outs and wells.
- Test well water every year at a certified lab, and after any change in smell or taste.
- If unsure, call a licensed pro before opening a tank or a wellhead.
Survey notes: sources for this page
- Fairfax County Health Department, onsite sewage and water. Opened November 3, 2026.
- DC Water, sewer backup. Opened November 3, 2026.
- Alexandria sewer and hydrant maintenance. Opened November 3, 2026.
- Arlington County, sewer. Known to us only from a search listing of the page; the site would not open for us.
- Town of Herndon, water and sewer. Known to us only from a search listing of the page.; not opened.
- Town of Vienna, water and sewer. Known to us only from a search listing of the page.; not opened.