The crawlspace under our house has a tendency to get a bit muddy when the rains are heavy and then dry up a few days later. When the rains are especially hard water will collect in a pit in the crawlspace and I have to go in with a wet vac to clear out the puddle that has formed.
I've had this explained to me by a contractor as the high water table which comes and goes with the tide (I live in Berkeley, CA) and not something to worry about. Other contractors are pointed it out as a concern. Our neighbors have a sump pump to keep their basement dry.
How do I know if I need a sump pump? What are the risks of not getting one right away? How hard is it to install myself? The house is 100 years old, I assume it's been standing this whole time without one.
Best Answer
A sump is easy enough to install DIY. You need a precast concrete sump well (mostly to keep muck out of the pump,and keep the float switch clear), a pump, a place to dump the water to, and a GFCI electrical outlet. In general the water needs to dump outside, not to a sewer.
In Berkeley CA you likely have heavy clay soils that don't drain quickly. The tides seem an unlikely source of your problem.
As to effect on the home: wet soil expands somewhat compared to dry soil. If only part of the crawl gets wet, that can create differential stresses on the foundation, leading to uneven settling and cracking.
The problem can also be solved with perimeter drains, keeping the water outside in the first place.
One issue you'll face is it's hard to find a good quality sump pump that has low capacity. The smaller (capacity) pumps tend to be cheaper (quality) pumps.