Rainwater in our basement

Noah Davis
15 days ago

Last August, we bought our first house in Seattle. In our first winter in the house, Seattle had massive rainstorms (even for Seattle), causing rainwater to leak into our basement. We had to rip out about 2 tons of wet carpet :(

After the first big storm, I realized I had not even done even the bare minimum to ensure our house was draining properly. We had clogged gutters, leaking downspouts and gutters hanging off the fascia. The first step was just to ensure all of this was in order.

Those changes had an impact, and in a regular rainstorm, our basement stays dry.

However, during a massive downpour (say, over 1" of rain), our basement gets water, mostly on one side of the house. A puget sound architect I asked about this situation said that underneath about 30" of dirt there usually resides a hard, glacial till material that is essentially impermeable. He did not evaluate our house but the sense I'm getting is that hydrostatic pressure builds up from underneath our house causing groundwater to get pushed through the area of least resistance -- aka into our basement.

I've had 4 waterproofing companies come out to provide us with an estimate. Their estimates range from $8k to $18k with most recommending an interior perimeter drain and a sump pump.

I'm at the point where I'm going to pull the trigger with one of these companies, but am slightly uncomfortable with spending this much money without getting 3rd party validation that this is the right direction to go. The waterproofing companies I'd go with have good reputations, but are still incentivized to offer the most expensive option.

I'd be happy for any opinions this community in terms of how to evaluate these proposals. Right now, I'm using the following criteria:

  1. Guarantees -- length, transferability
  2. Customer references
  3. Price
  4. Asking around / common sense about the solution presented

Am I approaching this the right way? Should I be considering other options? Are there professional, objective 3rd party evaluations I could get done?

Thank you.

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