Serving San Mateo
Groundwater & Basement Water Intrusion in San Mateo, CA
Basement seepage, failed sumps, and hydrostatic pressure against the foundation are extracted and dried, and the path from the ground is identified so the loss does not repeat. Groundwater and basement seepage are extracted and dried only after the path from the soil is identified — a wall, a slab, a drain, or a failed sump. Drying the interior without stopping that path returns the same water to the same floor.
Frequently asked questions
The creek is small and a long way off.
Its size at the bridge is not the useful measure. It falls steeply out of the hills and then has almost no gradient left once it reaches the flats, so it backs up across a wide area rather than running deeper in its channel. Distance from the bank matters much less here than elevation relative to it.
Nothing happened in the first storm of the season.
The first storm goes largely into dry ground. The damaging ones are usually third or fourth in a sequence, landing on a soil profile that is already full and a creek that has not come back down. Winters here deliver in trains, and it is the cumulative position rather than any single total that decides the outcome.
Part of this neighborhood is on old bay fill.
Some of it is, and fill settles for decades after it is placed. That pulls buried pipe out of the grade it was laid at, so lines that drained correctly when installed now hold water or run backwards. It shows up as a drainage fault rather than a settlement one, which is why it often gets misdiagnosed.
These questions come from the San Mateo page.