The first hour after a basement floods in a DC rowhouse

Is it safe to step into the water at all?

Look before you walk down the stairs. In many DC rowhouses the electrical panel, the washer and the water heater all sit in the basement, often along the same wall where water collects. If water is touching outlets, power strips, extension cords or the bottom of the panel, stay on the stairs. Don't reach across a wet floor to flip a breaker.

If the panel is upstairs, or on a dry wall you can reach without standing in water, switch off the basement circuits with a dry hand while standing on a dry surface. If you can't reach it safely, call Pepco and ask for power to be cut at the meter, or call 911 if anything is sparking or smoking. No belonging is worth an electric shock.

Two more checks take seconds. Sniff near the furnace and water heater for a rotten-egg odor; if you smell gas, leave the house without touching light switches and call 911 or Washington Gas from outside. Then look at the water itself. Brown or gray water, toilet paper, or a sewage smell rising from the floor drain means you are dealing with sewage, and nobody should wade through it in sneakers.

How do you stop the water if it is still coming in?

The fix depends on where the water starts, so spend a minute finding the source. A spray from a pipe or a hissing fitting is a supply leak. A spreading puddle under the water heater usually means a failed tank or relief valve. Water entering at the base of a wall or under the front door during a storm is rain or groundwater, and water bubbling up from the floor drain is a drain or sewer problem.

Once you find the main shutoff, tag it with bright tape so you can find it in the dark next time.

• Supply pipe or fitting: close the main shutoff, usually on the front basement wall where the line enters from the street, sometimes behind a panel or under the front steps.
• Water heater: close the cold inlet valve on top of the tank, and turn a gas unit's control to off or pilot.
• Washing machine: close both hose valves behind the machine; unplug it only if the plug and the floor around it are dry.
• Floor drain backing up: stop running water anywhere in the house. No flushing, no laundry, no dishwasher until the drain stops rising.
• Storm water at the door: if there is no lightning and the stairwell is not deep with water, scoop leaves off the drain grate at the bottom of the front steps.

What photos will an insurance adjuster want later?

Take pictures before you move or throw out anything. Phones date-stamp every image, which helps when a claim is reviewed weeks later. Start wide from the bottom of the stairs, then work around the room.

Keep damaged items until your insurer says you can discard them, or at least photograph each one and save a small cutting of carpet and pad. Coverage varies widely: sudden pipe bursts are often covered, while sewer backups and surface flooding often need a separate endorsement or a flood policy, so check your policy before assuming either way. Our guide to organizing photos and receipts for a water claim covers the paperwork side.

• A short video walk-through, narrating what you see and where the water came from
• The water depth: stand a tape measure in the deepest spot and photograph the reading
• The source itself: the split pipe, the rusted tank bottom, the overflowing drain
• Model and serial plates on the furnace, water heater, washer and dryer
• Water lines on walls, furniture legs and boxes, since they fade as things dry

Which belongings should you move first?

Once the area is safe, lift things in order of what cannot be replaced or dried. Paper and photos come first: tax files, passports, family albums and kids' artwork wick water fast and grow mold within days. Lay wet photographs face up on a towel upstairs, and freeze soaked documents in zip bags if you can't dry them soon.

Electronics come next, but only if they are already unplugged or you can unplug them without standing in water. Then roll up area rugs so their dyes don't bleed into the carpet or floor below, and move them somewhere they can drain. For furniture too heavy to carry, slide foil squares, plastic lids or wood blocks under the legs so the wood stops wicking water and stains stay off the carpet.

Stack cardboard boxes on a dry floor upstairs, not on the stairs, where wet boxes collapse and block your way out. Anything touched by sewage should be bagged and set aside for a decision later.

What should you avoid doing, even with good intentions?

Most of the extra damage we see after a basement flood comes from well-meant shortcuts in the first hour.

• Don't use a household vacuum on water. Upright and canister vacuums are not built for liquid and can shock you or burn out; only a wet/dry shop vac plugged into a dry, grounded outlet belongs near water.
• Don't point fans at sewage-contaminated areas. Moving air lifts droplets and dried residue and carries them into the rest of the house.
• Don't pump out a deeply flooded basement in one go while the ground outside is saturated. Pressure from waterlogged soil can crack or bow walls, so FEMA advises lowering deep water gradually, about a third per day.
• Don't relight a furnace or water heater whose burner or controls sat in water. Gas valves and igniters need to be checked first.
• Never mix bleach with ammonia or other cleaners, and skip bleach on drywall and bare wood, where it does little beyond the surface.
• Don't crank up the heat to dry things out. Warm, wet air with nowhere to go speeds mold growth in drywall and carpet pad.

When is it time to call for professional drying?

A small spill from a washer hose on bare concrete is often something you can handle with a shop vac, towels and a dehumidifier. The calculation changes quickly. Call when water covers more than a small area, when it has soaked into carpet pad, drywall or a finished floor, when it came from the floor drain or smelled like sewage, or when the basement is a rented apartment with walls and flooring you can't pull up yourself.

Time matters because mold can start growing on wet building materials within 24 to 48 hours. Our technicians begin by extracting the standing water, then map moisture with pin meters and a thermal camera to see how far it wicked into walls and framing. The drying equipment stays on site and gets checked daily until readings return to normal, which in most basements takes three to five days. If the floor drain was the source, the job follows sewage cleanup procedures instead, with protective gear and removal of porous materials.

Not sure whether you have a sewer problem or groundwater? Our piece on telling sewer water from groundwater walks through the clues. When you're ready, call (202) 989-3053. The line is answered 24/7, and we can talk through what you are seeing before anyone touches the water.

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