Damp block basement wall with a moisture line

Janesville, Wisconsin

Basement Waterproofing in Janesville, WI for Wet and Flooded Basements

We waterproof basements in Janesville, WI, where about 27% of occupied homes were built before 1960 and about 56% before 1980, and where the ground takes about 37 inches of precipitation and about 37 inches of snow a year. On April 17, 2026, flash flooding sent storm runoff into Janesville basements, and city figures put the damage above $30 million. Call 123-456-7890 for a free estimate.

Call 123-456-7890 Our services

Interior drainage and sump pumps
Exterior waterproofing
Basement wall repair
Free written estimate
Janesville and Rock County

A wet basement comes down to water pressure. Rain and melting snow soak the ground around the foundation, the soaked ground pushes against the walls, and that pressure forces water through cracks, mortar joints, and the seam where the wall meets the floor. Paint and surface sealers fail because the pressure behind them stays. We take the pressure off the wall and give the water a path out.

Basement with wet patches on the floor and a homeowner looking at them

What we do

Our Basement Waterproofing Services in Janesville

Water enters Janesville basements in a few different ways, so we pick the method by where the water comes from and how the foundation was built.

We install interior drainage and sump pumps in Janesville

We cut a channel in the slab beside the footing, lay perforated pipe in gravel, and run it to a sump basin where the pump sends the water outside. On block walls, we drill weep holes in the bottom course so water inside the block drains into the system instead of sitting in the wall. We add a battery backup to the pump so it keeps running when a storm cuts the power. It's the least disruptive method, and it can go in during any season. Interior drainage and sump pumps

We waterproof Janesville basements from the outside

When water pushes against the wall from the soil, we dig down to the footing, clean the wall, and apply a membrane with exterior drainage. It's a bigger job, and it stops the water before it reaches the foundation. Exterior basement waterproofing

We repair cracked and bowing basement walls in Janesville

Soil and water pressure push block and poured walls inward over time. Depending on how far a wall has moved, we seal the crack or stabilize the wall with anchors or carbon-fiber straps. Basement wall repair

We also handle window wells, crawl spaces, and yard drainage

Window wells get drains and covers, crawl spaces get a moisture barrier and drainage, and yard drainage carries roof and surface water away from the house.

Work is performed by independent professionals. Every project starts with an inspection and a written price before any work begins.

Why Janesville Basements Take On Water

Weather loads the ground all year. The Afton-Janesville weather station records about 37 inches of precipitation and about 37 inches of snowfall in an average year, with snow falling from November into April. March to June is the wet stretch, at about 14.7 inches of precipitation, and June is the wettest month at close to 5 inches. Glacial deposits cover most of Rock County, according to the USGS, and the county's ground water is recharged mainly by local precipitation. That water goes into the ground around your foundation, and the foundation holds the pressure.

Freeze and thaw does the rest. March in Janesville averages a high near 45°F and a low near 25°F, so the ground and the walls cross freezing almost every day. Water that gets into a crack or mortar joint freezes, expands, and opens the gap a little more, and each thaw lets in more water. A hairline crack in fall is often a steady leak by spring.

The houses add to it. Census figures show about 27% of Janesville's occupied homes were built before 1960, and the largest single group, about 28%, went up between 1960 and 1979. Basements from those decades went in before modern drainage, and the block and poured walls of that era take on water through cracks, mortar joints, and the floor-wall seam.

The Rock River adds a risk of its own. In June 2008, the USGS counted Janesville among nine severely damaged southern Wisconsin communities, with the Rock River not peaking until June 21 at Indianford and Afton. We look at the river, the weather, and the foundation together when we inspect. Rock River flooding and Janesville basements

The April 2026 Flood and What It Means for Your Basement

On April 17, 2026, flash flooding hit Janesville and southern Wisconsin, and storm runoff flowed into residents' basements. City figures reported by WKOW on May 1, 2026 put the damage above $30 million, including about $26 million in personal property and about $7 million in public property. Cleanup companies worked around the clock for days, and the Rock River overflowed its banks. The National Weather Service's review of the storm said flash flooding was particularly severe in the Janesville area, with numerous water rescues, after training thunderstorms dropped repeated heavy rain on already saturated soils. The Wisconsin State Climatology Office put estimated rainfall across the Janesville area near 10 inches, well above the area's two-day 100-year rainfall threshold of 7.44 inches.

If your basement took water that night, or has taken on water in storms since, we inspect where it came in. Water finds the same entry points each time, whether it's the floor-wall seam, a window well, a cracked wall, or a sump that couldn't keep up. We trace the path, price the fix in writing, and install the drainage and pump capacity the house needs. If the basement is still wet, our guide to the first 24 hours after a basement floods covers what to do now.

Signs You Need Basement Waterproofing

A wet basement tends to show itself in stages. These are the signs to watch for in a Janesville home:

Standing water or damp patches on the floor after rain or snowmelt
A tide line or staining along the bottom of the walls
White, chalky residue on block or concrete, called efflorescence
A musty smell that lingers even when the floor looks dry
Cracks in the walls or floor, especially ones that widen over a season
Walls that bow inward or lean
A sump pump that runs constantly, or never runs at all
Rust on appliances, or warping on anything stored against a wall

One sign is worth watching. Several together mean water has found a way in, and tracing it early keeps the repair small.

Why us

Why Homeowners Choose Us

Built around Janesville homes. We plan the work around Janesville's 1960s and 1970s basements, its spring snowmelt, and the Rock River, not a one-size script.
A free, no-obligation estimate. Every job starts with an inspection and a written price, so you know the scope before you decide anything.
Prices set before work. The written price is the price, with nothing added after.
The right-sized fix. We match the method to the problem: interior drainage, exterior work, or wall repair, and nothing the foundation doesn't need.
Sump pumps that keep running. We size the pump to the water and add battery backup so a power outage doesn't turn a storm into a flood.

How it works

How We Work

First, we inspect the basement and the foundation inside and out to find where water enters and why.
Second, we write up a plan and a price for the work the house needs.
Third, our installers do the work.
Finally, we test the sump and the discharge before we call the job done.

Permit rules are set locally, and the City of Janesville and the Town of Janesville are separate jurisdictions, so we confirm what the local building department requires before work starts.

Already Have a Quote?

If another company has given you a price, call 123-456-7890. We'll inspect the same basement and put our plan in writing, so you can compare the two side by side and see whether the method, the scope, and the price fit your foundation.

What a Good Waterproofing Quote Includes

Two prices mean something only when they describe the same work, so compare quotes on these points:

The method. The quote names the system: interior drainage, exterior waterproofing, wall repair, or a mix.
The scope. It states how many feet of wall or floor edge the work covers and where it begins and ends.
Where the water goes. It shows where the sump pump discharges and whether a battery backup is included.
The warranty. It lists in writing what is covered, for how long, what voids it, and whether it passes to the next owner.
The permit. It says who handles any permit the job needs.

Our written plan covers each of these before work begins.

What Basement Waterproofing Costs in Janesville

Interior drainage costs less than exterior excavation, and wall repair has its own range. Published 2026 national cost guides put interior waterproofing at roughly $3,000 to $12,000, exterior waterproofing at roughly $7,000 to $18,000, and an installed sump pump at roughly $600 to $2,500. Wall repair has no single typical figure, because the price follows how far the wall has moved. What basement waterproofing costs, and what changes the price

Those are national averages, not Janesville quotes. The length of wall treated, the foundation's condition, and whether a sump and battery backup are added all move the number, and most homes need just one approach. A real price for a specific home comes from an on-site inspection.

Areas We Serve Around Janesville

We waterproof basements in Janesville and across Rock County, including Beloit, Milton, Evansville, Edgerton, Clinton, Orfordville, and Footville. See the full service area

Frequently asked

Frequently Asked Questions

Why does my Janesville basement leak after heavy rain?

Rain and snowmelt soak the ground around the foundation, and the soaked ground pushes water through cracks, mortar joints, and the floor-wall seam. In Janesville, the Afton-Janesville weather station records about 37 inches of precipitation a year, and block walls from the 1960s and 1970s give the water an easy way in. Surface sealers rarely last because the pressure behind the wall stays, so a lasting fix sends the water to a sump.

Do I need interior or exterior waterproofing?

Interior drainage suits water that gathers inside at the floor joint, and it costs less, causes less disruption, and can go in during any season. Exterior waterproofing suits water pressing against the wall from the soil, and it means digging down to the footing to seal the wall from outside. Many Janesville homes do well with interior drainage, and an inspection settles which method the foundation needs. Interior vs exterior basement waterproofing

Does homeowners insurance cover a wet basement?

Most homeowners policies exclude groundwater, flood, and gradual seepage, which cause most wet basements, and many exclude sewer and drain backup unless you add an endorsement. The federal flood insurance program's FloodSmart site states that most homeowners insurance does not cover flood damage. Read your policy and ask your insurer about groundwater, flood, and sewer backup, because coverage differs from policy to policy.

Does basement waterproofing need a permit in Janesville?

Permit requirements depend on the job and on the property's location, since the City of Janesville and the Town of Janesville are separate jurisdictions with their own rules. We confirm what the local building department requires for your specific work before it starts. Call 123-456-7890 and we'll check it for your address.

How much does basement waterproofing cost in Janesville?

National cost guides published in 2026 put interior waterproofing at roughly $3,000 to $12,000, exterior waterproofing at roughly $7,000 to $18,000, and an installed sump pump at roughly $600 to $2,500. Those are averages, not Janesville quotes. The price for a specific home depends on the method, the length of wall treated, and the foundation's condition, and an on-site inspection gives the real number.

Which areas do you serve?

We serve Janesville and Rock County, including Beloit, Milton, Evansville, Edgerton, Clinton, Orfordville, and Footville. Call 123-456-7890 to confirm coverage for a specific address.

Get a Free Estimate in Janesville

For basement waterproofing in Janesville, call 123-456-7890 for a free estimate. You can also reach us here.

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