Most of the time, water sneaks into your home and rests unobserved in your crawl space for a long time before anyone even knows it is there. Most home owners that I speak with that have standing water in their crawl space, found out only when they put their home up for sale and had a grim report from the home inspector.
Since standing water in the crawl space can be so destructive, it is important to identify it early and take care of it quickly. That brings me to my first tip:
#1 – Check your crawl space every 6 months
Here is the problem, most people have never even been in their crawl space. Some people don’t even know how to get in it! So, how are you going to know when you have water? You have to look!
Look, I’m not telling you that you have to suit up with a respirator, gloves and flashlight and crawl around down there. I am only suggesting that you open the hatch and shine a flashlight down there. If you have a really bad problem, it will be pretty obvious.
#2 – Determine if water is sloping towards your crawl space vent
The most common way that water accumulates in your crawl space is from water pouring into the foundation vent. Take a walk around your house and see if the ground is sloping towards a vent. Make sure that the vent is above ground level and if it is not, get a shovel and start digging it out.
I recently bought a home that had a very obvious slope towards one of the foundation vents. I didn’t have to wait until it started raining to know that this was going to be a problem, so I dug it out and put in a simple french drain to divert the water away from the house.
#3 – Put in a french drain
Speaking of putting in a french drain, that is actually a great solution to solving water issues. Typically, a french drain consists of trenching with a slope towards a desired discharge point. I recommend digging the trench a minimum of 6 inches deep and placing a 3 inch perforated pipe in the trench with a geo thermal filter over it. Once the pipe is in place, you can cover the pipe with drain rock. Remember, the most important part of a french drain is making sure that it is sloping correctly towards a desired discharge location.
#4 – Install a sump pump
This is not the easiest DIY project, but it can be done. To do it right, you want to dig and install a sump basin at the lowest point in the crawl space (look for the area with the most pooling water). I would use 22 inch deep/ 18 inch diameter basin that can be purchased at Home Depot, but a bucket with 1 inch holes drilled into it would be sufficient. Once the basin or bucket is in place, place the sump pump in and plumb it to the outside of the structure. The best spot to plumb the discharge would be to tap into the underground gutter drain. This will usually be a 3 inch ABS pipe that flows directly parallel with the foundation and is generally buried about 12 to 18 inches deep. A couple things to note: First, to be up to code, you should have an electrician install a dedicated plug. Second, it is critical to use a backflow valve on the discharge plumbing.
#5 – Replace the vapor barrier
Sometimes water can get into the crawl space and rest on top of the vapor barrier for a long time. Maybe the water that got into the crawl space was an isolated event, but that is really hard to determine. One solution would be to replace the vapor barrier and all the standing water staining and put in a fresh one. Then, check the crawl space again in about 6 months and see if more water staining is present. If water is not present, it might be safe to assume that the water that got in previously will not be a recurring problem.