Cost guide · Greater Boston
How much does basement waterproofing cost in Lynn?
Most waterproofing projects in Lynn run $7,600 – $15,000, with a typical waterproofing project around $11,300. Adjust the estimate for your job below. Figures reviewed 2026-07.
Not sure which you need? Start with an inspection — many reputable companies assess free, and independent assessments run up to $500.
The wall run getting the drain — a full 30×40 ft basement is about 140 ft.
Estimated range
$7,600 – $15,000
Typical waterproofing project around $11,300
- Interior French drain
- $6,600 – $12,000
- Sump pump & basin
- $1,000 – $3,000
A ballpark from regional averages — not a quote. Your price depends on the specifics of the job, so get written quotes from two or three licensed pros before deciding.
How this estimate works
A ballpark from regional averages — not a quote. Your price depends on the specifics of the job, so get written quotes from two or three licensed pros before deciding.
- Interior drain pricing is Boston-area ($66–$120 per linear foot, with $66–$85 typical) and includes trenching the slab, drain tile, stone, and re-concreting; the sump line covers pump, basin, and discharge.
- Crack injection and exterior excavation bands are national figures ($300–$1,500 per crack; $100–$300 per foot) with the ~1.2× Boston uplift applied.
- Exterior work assumes accessible walls — decks, porches, pavement, ledge, and buried utilities push excavation past the band.
- If you're not sure which fix you need, start with an inspection: many reputable waterproofers assess free, and an independent paid assessment runs up to $500.
- None of these fixes replaces basic water management — grading, gutters, and downspout extensions come first and cost a fraction of any system below.
Ranges reflect published Greater Boston contractor pricing and regional cost data, last reviewed 2026-07.
What drives the price
The fix, not the foot, sets the budget
This trade has the widest honest price range in home services: a single injected crack and a full exterior dig-out differ by 20× or more. The first dollar-moving decision is diagnosis — where the water enters and how often — which is why a careful inspection is worth more than any per-foot rate.
How much perimeter is actually wet
Interior systems price by the foot ($66–$120 in Lynn), so a drain along one chronically wet wall costs a fraction of a full perimeter. Good contractors will say when a partial run is enough; be wary of quotes that jump straight to the whole basement without explaining why the water pattern demands it.
What's in the way
A finished basement adds demolition and refit to interior work; outside, decks, additions, pavement, and New England ledge can make excavation impractical along part of a wall. The same system varies by thousands depending on what has to be moved, cut, or restored — walk the contractor around everything touching the foundation.
Water management comes before waterproofing
Most wet basements improve when roof water stops landing beside the foundation. Regrading, gutter repairs, and downspout extensions cost a fraction of any interior system and make whatever you do install work better. An honest Lynn waterproofer checks the outside first — it's a good test of who you're dealing with.
Get real quotes from top-rated waterproofing contractors in Lynn
An estimate is a starting point — written quotes are the real number. These are the strongest waterproofing contractors on the evidence: reviews weighed across sources and licenses verified against the state registry.
Davie Mac Tile
Fixes prior contractors' errors4.5
Basement Waterproofing cost questions, answered
- How much does basement waterproofing cost in Lynn?
- Most basement waterproofing projects in Lynn land between $2,700 and $10,600, with the metro average around $4,100 — but the fix drives the figure more than the house does. Sealing a single foundation crack can run $360–$1,800, a full interior French drain system with a sump lands $5,000–$12,000 or more, and exterior excavation is the most expensive path per foot of wall.
- How much does an interior French drain cost in Lynn?
- Boston-area pricing runs $66–$120 per linear foot with $66–$85 typical — that covers cutting the slab, setting drain tile in stone, and re-concreting. Add $1,000–$3,000 for the sump pump, basin, and discharge line, and a full-perimeter system on a typical basement comes to $5,000–$12,000. Partial runs along the wet wall only are a legitimate way to phase the cost.
- How much does foundation crack repair cost?
- Injection repairs run $300–$1,500 per crack nationally, and Lynn-area pricing typically lands about 20% higher — figure $360–$1,800. A hairline shrinkage crack sealed with polyurethane sits at the low end; wider cracks needing structural epoxy sit at the top. If a crack is horizontal, widening, or offset, spend on a structural engineer's opinion before any sealer.
- Interior or exterior waterproofing — which should I choose?
- They solve the problem from opposite sides. An interior drain at $66–$120 per foot manages water that gets in, and works in almost any basement; exterior excavation at roughly $120–$360 per foot stops water at the wall but means digging up whatever is against the foundation — landscaping, walkways, decks. Exterior makes the most sense on an accessible wall, or when other excavation is already planned.
- Is a free waterproofing inspection trustworthy?
- Free inspections are the Lynn norm, and they're genuinely useful for scoping — just remember they're also sales visits, and this trade's fixes range from a few hundred dollars to five figures. For anything beyond a simple crack, get two or three bids, and consider a $300–$500 independent assessment from an engineer or home inspector with no system to sell; on a $10,000 decision it's cheap.