Key takeaways
- Check downspouts first; roof water dumping at the foundation causes more wet crawlspaces than anything else.
- Surface grading that slopes toward the house is the second most common cause and the cheapest to fix.
- A footing drain that has silted shut or never had an outlet is the usual cause on 1960s to 90s homes.
- A leaking water service line can also flood a crawlspace, usually on the side facing the meter; the meter test rules it in or out.
Why Kitsap crawlspaces get wet
Most of the peninsula sits on glacial till with a hardpan layer a foot or two down that water can't easily get through. Rain that falls on a lot either runs off on the surface or perches on the hardpan and moves sideways. A house foundation is a hole dug through that layer and backfilled with looser material, which makes it the lowest, loosest spot on the lot: exactly where perched water wants to go. The crawlspace under the house is the bottom of that hole. Keeping it dry means intercepting water before it gets there and giving whatever does arrive a way out.
1. Downspouts
Walk the house in a hard rain. A downspout that dumps at the foundation, overflows at the elbow, or connects to a buried line that doesn't go anywhere is putting hundreds of gallons against the foundation in every storm. Buried downspout lines on older homes are frequently crushed, separated or clogged, and on some homes they were never installed. Fixing downspouts is the highest-return drainage work there is.
2. Grading
The ground should slope away from the house on every side. Decades of landscaping, settled backfill and added beds often reverse that, so the first few feet around the foundation slope inward. Regrading and, where needed, a shallow swale to carry surface water around the house solves a lot.
3. Footing drains
A footing drain is the perforated pipe around the base of the foundation that collects groundwater and carries it to an outlet. On Kitsap homes from the 1960s through the 1990s it's usually thin corrugated pipe laid without filter fabric or clean rock, and after thirty years it's silted shut. On older homes there may be none. And on a lot of homes the outlet, a daylight pipe somewhere downhill, has been buried or crushed so the drain fills and overflows into the crawlspace. Finding and testing the outlet is the first diagnostic.
4. Groundwater from uphill
On a sloped lot, water perched on the hardpan moves downhill toward the house all winter. A curtain drain, a French drain across the slope uphill of the house, intercepts it and carries it around. This is the fix for the bluff and hillside lots in Port Orchard, Manchester, Enetai, Tracyton and Bainbridge where the crawlspace is wet even though the downspouts and grading are fine.
5. A leaking water line
The water service line enters the house through the foundation, usually on the side facing the meter. A leak on it near the point of entry floods the crawlspace from that side. The tell is water with no rain, or a crawlspace that's wet in August. The meter test settles it in five minutes.
The order matters
Downspouts and grading are cheap and solve many cases outright. Footing drains and curtain drains are excavation work and solve the rest. A leaking line is a different problem entirely. Diagnosing in that order keeps you from excavating a foundation to solve a downspout.
Written by the crew at 360 Leak Finders
We locate, excavate and repair buried water lines and exterior drains across Kitsap County, 24 hours a day. If this guide raised a question about your property, call (206) 354-9906.