Crawl space waterproofing pricing in NC
We charge $30 to $35 per linear foot for a crawl space drain and $1,200 to $1,600 for a sump pump. For an average crawl space, a drain and pump system comes out to about $7,900. This price includes the trench, gravel, drain pipe, sump pump, basin, and discharge line.
If water only comes in at one spot, or the problem is gutters and grading, waterproofing costs far less.
Waterproofing deals with liquid water. It collects the water that gets into your crawl space and sends it back outside. It does not control humidity in the air, so many homes also need a vapor barrier or dehumidifier. We cover that below.
Please see below for a full breakdown of our costs.
Crawl space waterproofing pricing at a glance
Drain and sump pump system (the full waterproofing fix)
Average home total: about $7,200 – $8,600
Crawl space drain: $30 – $35 per linear ft.
Sump pump install (includes basin): $1,200 – $1,600
Other solutions that often go with waterproofing
- Dehumidifier install: $2,500 – $2,900
- Vapor barrier install only: $1.70 – $2.20 per sq. ft.
For our full pricing, see our pricing page.
What waterproofing includes
Waterproofing is a group of fixes, and the right one depends on where your water comes from.
Crawl space drain. We dig a trench along the inside of the foundation walls, set a perforated pipe in gravel, and route the water toward a sump pump. Water in the soil follows the drain instead of pooling under your house.
Sump pump. The pump sits in a basin at the low point of the drain. When water collects, the pump pushes it out through a discharge line and away from your foundation.
Exterior fixes. Gutters, downspout extensions, grading, and vent wells keep water from reaching the foundation in the first place. These cost less than interior drains, and they solve a lot of crawl space water problems on their own.
Crawl space waterproofing options, from most to least comprehensive
We recommend the most complete fix first, then walk down to the less expensive ones. Pick the lowest option that solves your actual problem.
Drain, sump pump, vapor barrier, and dehumidifier. This covers water coming in from the soil and moisture rising from the ground into the air. It fits crawl spaces with standing water plus high humidity.
Exterior fixes only. If the water comes from a downspout dumping next to the foundation or soil sloping toward the house, correcting that can end the problem without any work under the house.
Drain and sump pump. This fits crawl spaces that take on water during heavy rain but stay reasonably dry otherwise.
Sump pump only. If water collects in one low spot, a pump in a basin may be all you need.
Why we look at where the water comes from
Water in a crawl space almost always has a source, and the source decides the fix.
Water from one spot
Water entering one corner or one wall often traces back to one cause:
- A downspout emptying next to the foundation
- Soil that slopes toward the house
- A clogged or overflowing gutter
- A leaking plumbing or HVAC condensate line (this is a plumbing repair, not waterproofing)
In these cases we fix the source first. You may not need an interior drain at all, and we would rather tell you that than sell you one.
Water throughout the crawl space
Water showing up along multiple walls, or standing across the floor after most heavy rains, points to groundwater. North Carolina gets a lot of rain, and the clay soil common around Charlotte and the Piedmont drains slowly, so water can sit against foundation walls and work its way in. A drain and sump pump give that water a path out.
Signs your crawl space may need waterproofing
- Standing water or muddy soil a day or two after rain
- Water marks on piers, foundation walls, or the ground
- A musty smell coming up through the floor
- Mold or wood rot on the joists
- A vapor barrier that sits wet or has water pooling on top
Seeing one of these doesn’t mean you need a full system. It means someone should look at where the water enters and how much there is.
Waterproofing vs. encapsulation
These two get mixed up all the time.
Waterproofing handles liquid water from rain and groundwater. Encapsulation handles moisture in the air and rising from the soil, using a sealed vapor barrier, sealed vents, wall insulation, and a dehumidifier.
If your crawl space has standing water, waterproofing comes first, because a vapor barrier laid over wet ground doesn’t do its job. If your crawl space stays dry but humid, you likely need encapsulation and no drain at all. Some homes need both, and in that case we install the drain and pump before the vapor barrier goes down.
What drives the price up?
- Length of drain needed
- Surface the drain goes through (dirt costs less than concrete)
- Number of sump pumps needed
- Distance to the discharge point
- Accessibility (low and tight crawl spaces increase work time)
- Amount of standing water to clear before work starts
- Whether a vapor barrier or dehumidifier is added
What does an average cost home look like?
We’re used to dealing with wet crawl spaces, so yours may not be as bad as you think. On our pricing page, an average home has:
- 1,700 sq. ft. crawl space
- Crawl space height of 3 ft.
- Roughly 200 linear feet of drain
- One sump pump with basin
Who needs exterior fixes only?
Exterior fixes make sense when:
- Water enters at a single spot near a downspout or low-lying grade
- The water stops within a day of rain ending
- There is no standing water across the crawl space floor
- The soil and wood in your crawl space are dry otherwise
Downspout extensions are inexpensive and many homeowners can add them on their own. If you try that and the water keeps coming, the cause is likely groundwater, and a drain system is the next step.
What about basement waterproofing?
Basements are less common in our area, but we do install drains in them. Because the drain has to be cut into the concrete slab, basement drains cost more: $105 to $120 per linear foot, with an average job around $16,300.
Get your crawl space looked at
Every crawl space takes on water in a different way, so we have to look at yours before we can price it. A member of our team will inspect your crawl space, find where the water comes from, and take pictures so you can see it too.
At Walsh Crawl Space and Structural Repair, we explain what we find and lay out the solutions with the most affordable option that solves the problem. If you have water in your crawl space, give us a call or fill out our form to schedule a free inspection.
