Skip to content
NoVA & DC Plumbing Map

Sheet 13 of 18 · Fairfax County

Great Falls: check for a well and septic

Full map

Before anything else, find out whether your Great Falls house runs on public water and sewer or on a private well and septic system, because the Fairfax County Health Department governs the second kind.

Sheet revised November 3, 2026 · who makes this map

Red brick Colvin Run Mill with its water wheel and split-rail fence
Colvin Run Mill, in the Great Falls area of Fairfax County.
Who does what here
WaterPublic water comes from Fairfax Water, which owns the line through the meter. A private well is the owner's own responsibility, and the Health Department says a well owner is responsible for the water's safety. source
SewerPublic sewer is run by Fairfax County Public Works. A septic system is overseen by the Health Department's Onsite Sewage and Water Program, 703-246-2201. source
PermitsSeptic and well construction permits are applied for through the county's PLUS portal and reviewed by the Health Department. Plumbing inside the house goes through Land Development Services. source
LicensingContractors who pump septic tanks must enter the pump-out details into PLUS afterward; check a contractor's state license separately. source
Lead pipesA well has no utility service line to inventory. If you are a Fairfax Water customer, ask the supplier about your own line. source

Two kinds of house, one mailing name

Great Falls is a mailing and community name inside unincorporated Fairfax County, so the same county offices cover it as cover McLean. What differs is how a lot is served. We could not confirm from the county's pages which Great Falls streets have public sewer or public water. The only way to know is to check your own lot.

Water pouring through dark rock channels at Great Falls of the Potomac
The Great Falls of the Potomac, on the Virginia side.

The septic rule most owners should know

Chapter 68.1 of the Fairfax County Code says an onsite sewage system that does not need a state discharge permit must have its tank pumped out at least once every five years. The Health Department puts it plainly: if it has been more than five years, or you do not remember, it is time. The contractor who pumps the tank then records the visit in PLUS.

Systems the county calls alternative have heavier duties. Those must be inspected annually by a qualified operator and sampled once every five years. If your house has one, the approval paperwork will say so.

Wells

The Health Department tells well owners to test annually for bacteria and chemical contaminants, and sooner if the smell, taste or look of the water changes. A new well needs a permit under the county's private well ordinance. A home kit for hardness, iron and pH tells you nothing about bacteria or chemical contaminants, so it does not replace laboratory testing or the department's advice.

For hardness, iron and pH only, alongside a certified lab test and never in place of one: a hardness, iron and pH test kit at Quality Water Treatment (that store has the same owners as this map).

Blue well pressure tank with gauge in a utility room
A well pressure tank in a utility room. AI-generated picture.

Grinder pumps, if your house has one

Some homes sit where gravity cannot carry sewage to the main, so the county serves them with low-pressure systems that use a grinder pump. The county's rule is blunt: residents maintain and operate their pumps and bear damages from pump failure, and a buyer must acknowledge that duty in writing. Report a pump problem to the 24-hour line, 703-323-1211. Whether any Great Falls house has one is a question for your own deed and the county.

For the wider picture, see wells and septic and who owns which pipe.

What the map can't tell you

  • Whether your street is on public sewer. We found no list of Great Falls streets in the sources.
  • The age or condition of your tank, drain field or well. Only your records or an inspection show that.
  • Whether a grinder pump serves your house. The county does not publish a Great Falls list that we could read.
  • Which tests a lab will recommend for your water. The Health Department can advise.

Check your own address

  1. Look at your water bill. A Fairfax Water account suggests public water; no bill at all suggests a well.
  2. Call the Health Department at 703-246-2201 and ask what it holds on file for your parcel, including pump-out dates.
  3. Find your last pump-out receipt; if you cannot, treat the tank as due and book a contractor.
  4. Ask your closing papers whether a grinder pump acknowledgment was signed.
  5. If sewage surfaces in the yard, keep children and pets away and phone 703-323-1211 or 703-246-2201.

More on checking an address

Survey notes: sources for this page