Back yard, stop 5 of 7

A well that went under floodwater

If a flooded well went under, don’t turn on the pump, and don’t drink or wash with the water¹. EPA says drilled, driven and bored wells are best disinfected by a well or pump contractor, with a bacteria test 7 to 10 days after¹. Use another water source until then.

Go to a dry spot where you can see the well head and pump house, and look from there.

Updated November 4, 2026, Midlands House Walk

The pump switch stays off, however much you want the water back. EPA’s reason is shock¹. Don’t touch any power while your feet are in water².

Air view of muddy water spread among trees, roofs on the higher ground — Brown floodwater through wooded lots, with houses on higher ground, Columbia, SC, October 5, 2015. Wells in low ground can go under in water like this.

Small wood-sided pump shed with a metal pipe rising next to it — A small wooden pump house with a metal well pipe, pines behind. Look for a mud line on the walls from where you stand. AI-generated picture.

Did water reach the well head?

Look for: Look for a mud line on the pump house, debris against the well pipe, or silt around it. Do this from the dry side and leave the switch alone.
What it tells you: A high water mark tells a contractor what to expect. EPA says wells over 10 years old or under 50 feet deep are likely contaminated even with no apparent damage¹, so a clean look doesn’t clear it.

Old hand pump and small motor on concrete beside a stained tank and block wall — An old hand pump and small electric pump on a concrete floor by a stained tank. Any pump that sat in water stays off.

Was the pump or tank in the water?

Look for: Look from the doorway for silt on the floor or a line on the tank. Note how high it got and how long it stayed, if you know.
What it tells you: EPA’s warning is about shock¹, and CDC says never touch power while standing in water². A contractor needs that high-water detail, so take a photo for them.

Mud spread over a roadway with fence panels lying flat and a toppled sign — Silt across a road and yard edge with fences flat after the October 2015 flood, Forest Acres community, Columbia, SC. Silt in your yard tells you how high it came.

What did the septic field get?

Look for: Look for silt and standing water over the field. If you have a septic system as well, this matters as much as the well. Keep cars off it.
What it tells you: EPA says not to use the system until water in the soil field is lower than water around the house³. South Carolina’s minimum spacing is 75 feet between septic and well⁴, so floodwater may cover both. See after a flood.

Sample container with a white lid standing next to a kitchen sink — A plain water sample container on a counter by the sink. Testing comes after the contractor has been, not before. AI-generated picture.

When does testing come?

Look for: Mark your calendar on the day the well is disinfected. The sample goes in 7 to 10 days later, and the lab decides what the answer is¹.
What it tells you: Clemson says well owners are responsible for testing, through the SC DES Private Well Program or labs⁵. Its pages may still say DHEC. Testing a private well has fees and wait times.

Does a utility boil notice speak for your well?

Usually not. A utility’s boil water notice speaks for its own system, so follow whatever the issuing agency says, and EPA’s flooded-well document for the well itself. The October 2015 rain dropped 10 to 20 inches from Columbia southeast across the eastern Midlands⁶, so flooded wells aren’t an abstract worry here.

Yours to do

Keep everyone off the well water for drinking and washing, and use another source¹.
Read EPA’s flooded-well document, which is the one to follow¹.
Photograph the water line on the pump house and tank before it dries.
Book the bacteria test for 7 to 10 days after disinfection¹.

For a licensed pro

A well or pump contractor for disinfecting a drilled, driven or bored well¹.
An electrician or the contractor to check pump power before it’s turned back on.
Trained specialists for any septic cleaning or repair after the flood, because of dangerous gases³.

Where this comes from

Keep walking (AI picture)Testing a private well in South Carolina