Lakefront crawlspace waterwhen pumping does not keep it out

A crawlspace on an inland hill gets water mostly from the side or from pipes. A crawlspace by the lake has another source: the water table. When the lake is high and the soil has been soaking for weeks, the ground around the house has nowhere to drain. Water finds its way up through the dirt floor, and it often appears in the lowest corner first. Everett Herald reporting described nearly a foot of standing water on one lakeside lawn over two winters. ^[2] A crawlspace on a lot like that could be wet long before water is anywhere near the floor.

The shoreline itself has been changed a great deal. HistoryLink notes that few nearshore lots kept their native vegetation, and that bulkheads and fill became common. Fill can drain differently from native soil, and a bulkhead holds back the land but does not stop water moving underneath or around it. So two neighboring houses can behave quite differently in the same storm.

See our main crawlspace water damage page for the general process. What follows deals with the shoreline.

Pumping feels like the obvious thing to do, but the answer depends on where the water comes from. If it came in from a storm or a pipe, and the ground around is not holding more, pumping it out makes sense and should be done soon. If the water table is high, you can pump all day and still watch it come back, because you are effectively trying to lower the water level of the ground around your house.

There is also a safety point. Washington's guidance on basements warns that draining a below-grade space too soon can push walls in or make floors heave, because the water inside helps brace the walls against the saturated soil outside. ^[5] It says to wait until most of the floodwater outside has receded and to pump at about the rate the outside water falls. A shallow crawlspace has less at stake than a full basement, but on lots with taller foundation walls it is worth raising this question.

If you have a sump, keep it running as long as it can do so safely. Ask where it discharges. Water sent out next to the foundation will soon return.

Crawlspace water raises hard questions, because the living space may be untouched. Washington's Insurance Commissioner says a typical home policy does not cover flooding, and insurers often treat ground water separately as well. ^[6] Flood policies have their own rules about what they cover below the first floor, and you should read yours closely instead of assuming either way. If a pipe under the floor caused the problem, that is a very different conversation.

Your dated photos and any record of the lake level help you explain what happened. National Flood Insurance Program coverage usually begins 30 days after purchase, unless a mortgage requires it, so it cannot be arranged at the last minute. Summer is a good time to talk to an agent. Ask specifically what is covered in a crawlspace.

You cannot change the lake, but you can limit how much extra water you add to the ground. Send downspouts away from the house, using solid pipe if you need to, and do not let them drain toward the low side of the lot. Keep vents clear, and make sure that no landscaping has buried them. Check the plastic ground cover in late summer, and repair it while the soil is dry. Move anything stored under the floor up onto shelves or out altogether. If you have a sump pump, test it in October, and look at where its outlet goes.