When we moved into our West Seattle home eight years ago, we knew from the previous sellers that part of the basement was prone to flooding in heavy rain. We also knew we weren’t the only ones – basement flooding is a common problem here, as most basements were unfinished and not originally set up as living quarters, and Seattle gets a good amount of rain that saturates the ground. While preventative measures aren’t foolproof, there are definitely things you can do to help lessen flooding damage before it starts.
Downspouts and gutters: Keeping gutters clear of debris is a given in any area, but allowing too much buildup in a gutter will force rain over the sides, landing close to the house. As for downspouts themselves, if tying into the sewer or using a watering system to catch water (see Seattle’s Rainwise program!) isn’t an option, make sure that water from the downspouts is always flowing away from the house. Splash blocks are fine, but most hardware stores will also carry downspout diverters which will help get the water even further from your house.
Diverting rain away from the house is a major tool for stopping flooding, but that won’t necessarily solve all your problems. Another amazing tool to prevent flooding a sump pump.
Sump Pumps: If your basement is prone to flooding from saturate groundwater, installing a sump pump might be just the ticket. The pump will sit in a pit just under the basement flooring, with a discharge pipe that will run somewhere away from the house. As the pit fills with groundwater, the pump will automatically turn itself on to drain the water. Sump pumps run on electricity, but many have battery backups that will allow it to keep working even if the power goes out.
French Drains: French drains can be installed both inside and outside of the home, and consist of a pipe in a shallow trench that channels excess water to one place so that it can be diverted away. French drains work great with sump pumps, as you already have a way to clear the water that’s collected.
If you really want to make sure water doesn’t enter your Seattle area basement, you’ll want to call in an expert to analyze potential trouble spots and draft a plan. Basement waterproofing specialists can determine if you need drainage, foundation repair, moisture barriers, or something else. Be warned – this is no cheap repair. Waterproofing can cost well over $10,000 and require some serious excavation. It’s best to get a few quotes before agreeing to a large job. Here are a few well-known local companies: