Foundation and Drainage in Redmond, WA
Redmond's foundation calls are mostly about groundwater. Lots near Bear Creek, Evans Creek and the Sammamish River valley sit close to the water table, and crawlspaces there often take water every winter. Drainage repairs typically cost $4,000 to $25,000, sump systems $3,500 to $12,000, and encapsulation $8,000 to $20,000.
Redmond foundation and drainage costs
| Work | Typical Redmond range | Typical setting |
|---|---|---|
| Perimeter drain and sump | $6,000 – $18,000 | Crawlspaces near streams and the valley |
| Sump pump replacement | $1,200 – $3,500 | Existing systems |
| Footing drain replacement | $10,000 – $26,000 | 1970s – 1990s homes |
| Crawlspace encapsulation | $8,000 – $20,000 | Persistent humidity |
| Seismic bolting and bracing | $6,000 – $18,000 | Overlake and Idylwood homes |
Redmond lots and water
Valley and stream-side lots in the Sammamish Valley and near Bear Creek have high groundwater in winter. Crawlspaces fill from below, so drainage needs a sump that lifts water to an approved discharge point.
Hillside lots on the edges of Education Hill and along Lake Sammamish carry water downhill toward houses.
Subdivision drainage systems from the 1980s and 1990s, including footing drains and yard drains, are now old enough to clog or crush.
Aquifer protection and discharge
Parts of Redmond lie in critical aquifer recharge areas that feed the city's drinking-water wells. Projects there may face rules on excavation, infiltration and what can be discharged to the ground. Discharging drainage to the street or a neighbor's yard is generally not allowed; ask your contractor where water will go and confirm with the city.
Redmond foundation permits
Structural repairs and seismic retrofits need building permits. Drainage work in critical areas or connecting to the city storm system needs review.
Redmond foundation questions
Why does my crawlspace flood every winter?
High groundwater, failing footing drains or both. A sump system is often the reliable fix in stream-side neighborhoods.
Do I need a backup sump pump?
If your crawlspace depends on a sump, a battery backup or second pump is cheap insurance.
Can I discharge sump water to the street?
Generally not without approval. Ask the city about allowed discharge points.
Should I bolt my older Redmond house?
If it was built before 1980 and is not bolted, yes.