A wet basement is rarely random. Water follows predictable paths, and most basement floods come down to a handful of causes: saturated ground, a sump pump that fails, a drain that backs up, a window well that fills or water that is directed toward the house. Understanding which one applies to you is the first step to reducing the risk. For help after a flood, see our page on Annapolis water damage restoration.
The common causes
| Cause | How it happens | What helps |
|---|---|---|
| Saturated soil | Heavy or prolonged rain soaks the ground, and water finds cracks, joints and the floor. | Grading, gutters and drainage, and sealing or drainage work by a specialist. |
| Sump pump failure | The pump loses power, the float sticks, the line clogs or the pump simply wears out. | Testing, maintenance and a backup power source. |
| Sewer or drain backup | The line is blocked or overloaded, and water comes up through floor drains and basement fixtures. | Keeping grease and wipes out of the lines, a camera inspection and possibly a backwater valve. |
| Window wells and entry points | Water collects in a window well, stairwell or bulkhead and pours in. | Covers, drains and keeping them clear. |
| Plumbing failures | A water heater, supply line or washing machine hose fails in or above the basement. | Replacing aging parts and knowing where the shutoff is. |
Rain, soil and the foundation
When the soil around a foundation stays saturated, water pressure builds against walls and floors. Cracks, the joint where the floor meets the wall and gaps around pipes are the usual entry points. Seepage like this is a maintenance matter, and the Maryland Insurance Administration says it's generally not covered by homeowners or flood policies, so reducing it before it happens is worth the effort. A waterproofing specialist or a plumber can look at the specific problem.
Gutters, downspouts and grading
The cheapest fixes are often outside. Gutters that overflow, downspouts that discharge beside the foundation and soil that slopes toward the house all send water where you don't want it.
- Keep gutters clear, especially in fall.
- Extend downspouts well away from the foundation.
- Make sure the ground slopes away from the house, not toward it.
- Keep patios, walks and driveways from draining against the foundation.
Sump pumps: where they fail
A sump pump is only useful when it works during the storm, and storms are when power goes out. The weak points are predictable.
- Power. A pump can't run without electricity. A battery backup or other alternate power source helps.
- The float. A stuck float keeps the pump from starting. Test it by pouring water into the pit.
- The discharge line. A clogged or frozen line, or one that dumps water beside the house, sends the water back.
- Age and capacity. Pumps wear out, and an old or undersized pump can fall behind in a heavy storm.
The MIA says a sump pump overflow may be covered only if you bought a water or sewer backup endorsement, so check your policy as well as your pump.
Sewer backups and drains
Floor drains and basement toilets are the lowest openings in a home's plumbing, so a sewer backup shows up there first. That water is contaminated, and cleanup is a different job. See sewage backup cleanup. Keeping grease and wipes out of drains helps. A plumber can inspect an older line with a camera and talk to you about a backwater valve, a device meant to keep sewer water from flowing back into a house.
What to do if water is already in
Stay out until it's safe
Check for electrical hazards and gas before entering. The CDC says never to use electric tools or touch power while standing in water.
Find and stop the source
Shut off a plumbing leak, or confirm the storm has passed.
Document the damage
Photograph the water line and damaged items before cleanup.
Remove the water and dry
Deep water is often pumped out in stages. See basement flooding cleanup.
Fix the cause
A plumber or waterproofing specialist addresses why it happened.
Basements and Annapolis
In Annapolis, the cause may be the tide as well as the rain. The City says its lowest-lying areas include downtown, City Dock and Eastport, so basements and garages there can take on water during high tides. Communities near the shoreline, such as Annapolis Neck and Cape St. Claire, deal with saturated ground and storm surge. Our guide to tidal flooding in Annapolis explains what the City says about the pattern.
Storing things so the next flood costs less
- Use plastic bins on shelves instead of cardboard boxes on the floor.
- Keep documents, photographs and electronics out of the basement.
- Lift furniture and appliances onto blocks if the room has flooded before.
- Keep a clear path to the sump pit, the main shutoff and the electrical panel.