Does Your Crawl Space Need a Sump Pump? Find Out Before the Winter Rain.

It has been a dry year. Wake County spent much of it in drought, and calls about water under the house have been quiet. That quiet is not the same as a dry crawl space. A crawl space that took on water in a wet winter will do it again when the wet weather returns, and the seasonal outlook for this winter leans wetter than normal across the Southeast.

The useful thing about a dry spell is that you can look at a crawl space now, while it is dry, and see the record the last wet season left behind. That record tells you whether you need a sump pump before the rain makes the decision for you.

Read the Marks Past Rain Left Behind

• Dried mud lines on the vapor barrier, piers or foundation wall, showing how high water has stood.
• A fan of silt spreading from one side of the crawl space, pointing back at where water enters.
• A low corner where the liner has puddled, or where the soil is still darker than everywhere else.
• White, chalky deposits on block walls and piers. That is mineral left behind as water passed through the masonry.
• Rust at the base of metal support posts, and staining low on the lowest framing members.
• A musty smell that shows up in the house a day or two after heavy rain and then fades.

If you cannot get under the house safely, do not. That is a job for someone with the right gear, and it is part of any inspection we do.

When a Pump Is the Answer, and When It Isn't

A sump pump is for water that arrives from below or through the soil: groundwater rising in a wet season, water moving downhill through the ground on a sloped lot, water seeping in under the footing. It gives that water a low point to collect in and a way out.

It is the wrong first answer when the water has a simpler source, and those are common:

• Downspouts emptying at the base of the foundation instead of carrying water well away.
• Grading that slopes toward the house, or soil and mulch built up against the wall.
• Plumbing. A supply leak, a failed drain joint, or an air conditioner condensate line discharging into the crawl space can soak one corner for months and look exactly like groundwater.

Fix those first. They are usually cheaper, and a pump on top of an unfixed source just runs more often. A good inspection is mostly about telling these cases apart.

What a Good Crawl Space Installation Includes

• A lined pit at the true low point, where water actually collects rather than where it was convenient to dig.
• A way to route water to it. An interior drain along the wall carries water to the pit instead of leaving it to find the pit on its own. It is usually far less disruptive than digging up the yard outside.
• A check valve, so water in the discharge line does not run back into the pit every time the pump shuts off.
• A discharge that ends well away from the house, somewhere the water cannot soak straight back down to where it started.
• An alarm. A crawl space pump is out of sight, so you need it to tell you when it is in trouble.
• A battery backup. The storm that floods a crawl space is often the same storm that cuts the power.

Already Have One? Test It Now

A pump that has sat idle through a dry year is a pump nobody has checked. Pour a bucket of water into the pit and watch: the float should rise, the pump should start, the pit should empty, and the pump should stop. Then go outside and confirm the water came out where it is supposed to, and that the end of the discharge line has not been buried, crushed or landscaped over. Most residential pumps last around seven to ten years. If yours is older than that, or you do not know how old it is, this is the season to replace it, not January.

Triangle Reconstruction has been keeping crawl spaces dry across Wake and Durham counties and every county bordering them since 2012. If your crawl space shows signs of past water, or your pump has not been tested in a year, call (919) 924-7600 before the wet weather does the testing for you.