Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total waterproofing cost
$9,500
Drainage / membrane system
$7,200
Sump pump
$1,400
Crack injection
$900
Cost per linear ft
$105.56
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How to use this
- 1Enter wall length treated (linear ft).
- 2Enter method.
- 3Enter basement wall depth below grade (ft).
- 4Enter sump pump + basin installed ($).
- 5Enter battery backup pump ($).
- 6Enter cracks to inject.
- 7Enter cost per crack injection ($).
- 8Enter landscape / finish restoration ($).
- 9Read your total waterproofing cost on the right — it updates as you type.
- 10Hit Share to keep the scenario or send it to someone.
About this calculator
Basement waterproofing is quoted per linear foot of wall treated, and the method drives everything. Interior drain tile with a sump is the common fix: a channel cut in the slab at the footing, perforated pipe, gravel, new concrete, and a pump. Exterior waterproofing — excavating to the footing, cleaning and membraning the wall, and installing footing drains — solves the problem at the source but costs several times as much because of excavation and landscape restoration. This calculator prices your chosen method by wall length, adds sump and battery backup, and includes optional crack injection. 2026 US national averages run roughly $60-$110 per linear foot for interior systems and $150-$350 per linear foot for exterior work.
Worked example
Using the values the calculator loads with:
Inputs
- Wall length treated: 90 linear ft
- Method: Interior drain tile + sump — $80/ft
- Basement wall depth below grade: 7 ft
- Sump pump + basin installed: 1400 $
- Battery backup pump: 0 $
- Cracks to inject: 2
- Cost per crack injection: 450 $
- Landscape / finish restoration: 0 $
Results
- Total waterproofing cost: $9,500
- Drainage / membrane system: $7,200
- Sump pump: $1,400
- Crack injection: $900
- Cost per linear ft: $105.56
What each field means
Inputs
- Wall length treated (linear ft)
- The wall length treated used in the calculation, measured in linear ft. Starts at 90 linear ft so you have a working example on load. Accepted range: 10–500 linear ft.
- Method
- Pick the option that matches your situation — the maths changes per option. Choices: Interior sealing + minor drainage — $45/ft, Interior drain tile + sump — $80/ft, Exterior membrane, shallow — $150/ft, Full exterior excavation — $250/ft.
- Basement wall depth below grade (ft)
- The basement wall depth below grade used in the calculation, measured in ft. Starts at 7 ft so you have a working example on load. Accepted range: 3–12 ft.
- Sump pump + basin installed ($)
- The sump pump + basin installed used in the calculation, measured in $. Starts at 1400 $ so you have a working example on load. Accepted range: 0–5000 $.
- Battery backup pump ($)
- The battery backup pump used in the calculation, measured in $. Starts at 0 $ so you have a working example on load. Accepted range: 0–2500 $.
- Cracks to inject
- The cracks to inject used in the calculation. Starts at 2 so you have a working example on load. Accepted range: 0–20.
- Cost per crack injection ($)
- The cost per crack injection used in the calculation, measured in $. Starts at 450 $ so you have a working example on load. Accepted range: 100–1200 $.
- Landscape / finish restoration ($)
- The landscape / finish restoration used in the calculation, measured in $. Starts at 0 $ so you have a working example on load. Accepted range: 0–15000 $.
Results
- Total waterproofing cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Drainage / membrane system
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Sump pump
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Crack injection
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per linear ft
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Interior or exterior waterproofing — which do I need?
Interior drain tile manages water that reaches the footing and is the practical choice for most finished-basement seepage. Exterior work is warranted when the wall itself is failing, grading cannot be fixed, or you are already excavating for other repairs.
Do I need a battery backup sump pump?
If the basement is finished or storms in your area routinely knock out power, yes — a pump that cannot run during the storm that floods you is not protection. Backups typically add $600-$1,800 installed.
Will grading and gutters fix it instead?
Sometimes. Extending downspouts ten feet from the foundation and correcting negative grade solves a surprising number of wet basements for a few hundred dollars, and any honest contractor will suggest trying that first.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Basement Waterproofing Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/basement-waterproofing-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/basement-waterproofing-cost" target="_blank" rel="noopener">Basement Waterproofing Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Basement Waterproofing Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/basement-waterproofing-cost) (2026).