Get matched with top sump pump or interior foundation drains installers in Mill Valley, CA

Grab a ruler and an empty 18‑inch‑wide pit. During a steady rain, time how much the water rises in one minute. Multiply that depth (in inches) by 60 to calculate gallons per hour, then add 50% for safety. If the result tops 2,100 gallons per hour—about 35 gallons a minute—you’ll need a 3/4‑horsepower unit. Anything lower, and a 1/3- or 1/2-horsepower pump should do the trick.

Loud rattling, constant cycling, or shuddering vibrations are the pump’s way of telling you it’s on its last legs. Musty smells, higher electric bills, and visible rust are other red flags. If the unit is 10 years old or older and exhibits any of these symptoms, replace it before the next heavy rain turns your basement into a wading pool.

You don’t have to hire a licensed plumber, but you should still bring in someone who installs sump pumps for a living—whether that’s a plumber, basement‑waterproofing specialist, or experienced handyman. They know the local codes, can wire the pump safely, and will test the system before they leave. Skipping professional help might void the warranty and could leave you with a pump that fails when you need it most.

Not every basement needs a pump, but if your home sits in a floodplain, has a high water table, or has ever taken on water during a storm, a sump pump is inexpensive insurance. For basements that only struggle with condensation or the occasional damp spot, sealing cracks and improving drainage may be all that is needed.