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Q: How can you prevent basement flooding?

A: Basement flooding can be an all-too-common occurrence in the Pacific Northwest and potentially a serious problem.

Among the negative consequences associated with basement flooding — apart from the inconvenient mess — are respiratory problems stemming from chronically wet houses, the potential for long-term damage to the home’s structure, an increase in insurance rates and the depreciation of property value.

Some causes of flooding cannot be avoided or controlled by a homeowner, such as overflowing rivers or other natural disasters. But water can get into basements for a number of other reasons.

If your basement tends to flood during periods of heavy rain or rapidly melting snow, you could have a leak in the basement walls.

There could be poor drainage on your lot, or overflowing gutters or plugged downspouts could be the culprit.

Less-common reason for basement flooding include a blocked connection between your home and the main sewer in the street, or a backup of wastewater in the sewer system or your private septic tank.

If water is getting into your basement, the best way to diagnose the problem is to work your way down, starting with the gutters and downspouts.

If your gutters are clogged or your downspouts are not working properly to divert water away from your home, water can drain directly into the ground around your foundation.

Clean debris from gutters and downspouts, and consider replacing them if they overflow even when they’re clean.

Check to make sure your downspouts extend at least six feet from your basement wall, and make sure the water drains away from your house toward the street or the backyard.

If your gutters and downspouts are working correctly, inspect the foundation for cracks and check your lot’s grading. If the land around your home slopes toward your home’s foundation, that could be a real problem.

Homes settle over time, which may cause the land around a home to slope. In that case, you may need to consider filling in and grading the lot so that the land slopes away from the house and not toward it.

Depending on the severity of the problem, it may make sense to install one or more flood-proofing devices such as sump pumps or backflow valves.

A qualified plumbing contractor can help determine if one or both of those systems would be a good preventive plan for your home.

If basement flooding is still occurring after you’ve taken all the preventive measures available, consider installing impermeable floor and wall finishes like ceramic tile.

It will lessen the damage and make cleanup easier. Instead of carpeting, use area rugs, which can be removed and properly cleaned if the basement does flood.

It won’t prevent flooding, but having an insurance policy that covers basement-flooding damage is a good idea if your home has had a history of such problems. The policy should include sewer-backup coverage.

And keep policies and related records in a safe location that is easy to get to after a severe storm or other disastrous event.

HomeWork is the weekly column by the Master Builders Association of King and Snohomish Counties’ Remodelers Council about home care, repair and improvements. If you have questions about home improvement, send them to