Down Under Waterproofing | Free Honest Basement Assessment — NJ & PA
Down Under Waterproofing
Assessments Available
★★★★★ 4.9
Central New Jersey & Eastern PA

Before You Spend $20,000 on Waterproofing—
Get a Real Diagnosis.

Most wet basements are misdiagnosed. Other companies quote $15,000–$30,000 for full drainage systems when the real fix might be a $400 plumber. We’ll tell you the truth—even when it means we don’t get the job.

A homeowner in Mercer County had two other companies quote her over $20,000 each. We showed up, diagnosed the real problem: a cracked pipe. She paid a plumber $400. Her basement has been dry ever since.

We made $0 that day. That’s how we operate.
77+ Five-Star Reviews
$0 For Your Assessment
0 Unnecessary Upsells
Slots Available This Week

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We serve Central New Jersey & Eastern Pennsylvania

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We currently serve Central New Jersey & Eastern Pennsylvania. We’re expanding soon—check back or try another ZIP.

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◆ You Qualify

Tell us about your situation

Step 1 of 714%

How urgent is your situation?

What type of property do you own?

Where are you noticing the water?

Water from floors/walls usually means waterproofing. Ceiling leaks are typically plumbing or roofing—we’ll help you figure it out either way.

Did this appear after heavy rain?

Rain-related moisture often points to exterior drainage, while constant moisture may indicate groundwater or plumbing.

How long have you been dealing with this?

What is the property address?

So we can prepare for your on-site assessment

Almost done! Your contact info

We’ll reach out to schedule your free assessment
✓ 100% Free
✓ No Obligation
✓ Honest Diagnosis
100%
Honest Assessments
77+
Five-Star Reviews
$0
Assessment Cost
0
Unnecessary Upsells
The Honest Difference

We Lost a $20,000 Sale.
The Homeowner Was Grateful.

A homeowner in Mercer County was panicking. Water in the basement every time it rained. Two waterproofing companies had already been out. Both quoted her over $20,000 for full drainage system installations.

We showed up. Took our time. Looked at the actual source of the water. Asked the right questions.

“The water is coming from a cracked pipe in your utility room. This is not a waterproofing problem.”

We referred her to a plumber. The fix took one afternoon.

$20,000+
What others quoted
$400
What she actually paid

We made $0 that day. But that’s exactly why homeowners across New Jersey and Pennsylvania trust us with their basements.

We’ve seen wet basements caused by poor grading, clogged gutters, condensation, plumbing leaks, and window well drainage issues—none of which require a $15,000 waterproofing system.

When it IS a real waterproofing problem, we fix it right. French drains, sump pumps, interior drainage systems, exterior waterproofing membranes, foundation crack repair, crawl space encapsulation—with engineered plans and proper permits.

But we’re not going to sell you something you don’t need. Ever.

Why We’re Different

Most Waterproofing Companies Sell You the Most Expensive Fix.
We Tell You What You Actually Need.

✕  What Other Companies Do
✕ Treat every wet basement like a $20K drainage job
✕ Use scare tactics about mold and foundation failure
✕ Quote full systems when caulk or grading would fix it
✕ Non-transferable warranties that void when you sell
✕ Send commissioned salespeople to pressure you
✕ Skip permits and inspections to cut corners
✓  What Down Under Does
✓ Diagnose the actual source of water intrusion first
✓ Give honest assessments—even when it means no sale
✓ Recommend only what your basement actually needs
✓ Lifetime transferable warranty—stays with the home
✓ Owner-involved, engineer-backed assessments
✓ Pull all permits, handle all inspections ourselves
Common Scenarios

Not Sure What You’re Dealing With?

Here are the most common issues we see—and how we handle each one honestly.

💧

Water After Heavy Rain

Often caused by poor exterior drainage, clogged gutters, or grading issues. Sometimes it’s a simple fix that doesn’t require waterproofing at all. We’ll tell you which one it is.

Might not need waterproofing
💨

Persistent Dampness

Constant moisture regardless of weather usually indicates groundwater pressure, foundation cracks, or failed vapor barriers. This is often a real waterproofing issue—and we’ll explain exactly why.

Likely needs waterproofing
🧸

Musty Smell or Mold

That basement smell means excess moisture is present. We’ll find the source—whether it’s a waterproofing issue, a ventilation problem, or something else entirely.

Full diagnosis included
Lifetime
Transferable
Warranty
A Warranty That Means Something

When You Sell Your Home, the Warranty Goes With It.

Most waterproofing warranties have a clause buried in the fine print: “Non-transferable. Void upon sale of property.” Which means it’s a sales tool, not a real guarantee.

Our lifetime transferable warranty transfers to the new owner when you sell. Real value you can put in your MLS listing. Something that tells the next buyer: this basement was done right, by a company that still stands behind it.

Honest is honest: If the system is ever tampered with, the warranty doesn’t cover that. We believe in transparency, even about the fine print.
Real Reviews

What Homeowners Are Saying

From real homeowners across Central New Jersey & Eastern Pennsylvania.

★★★★★

“Walt and his team did a wonderful job. They completed the basement repair work and preventive measures in both areas. The work was done quickly, professionally, and with quality and great communication.”

J

Joe C.

Trenton, NJ

★★★★★

“One of the best experiences I’ve had with any contractor. They assessed the damage, provided multiple options, and executed the repair seamlessly. They kept everything tidy. Cannot recommend them enough!”

M

Monica M.

Freehold, NJ

★★★★★

“Walt is quick to respond and provided a quote in a timely fashion. The crew was prompt, courteous and cleaned up thoroughly. This is the second time we’ve worked with them—that says everything.”

R

Rebecca G.

Toms River, NJ

Our100%Guarantee

The Honest Assessment Guarantee

If we inspect your home and it’s not a waterproofing issue, we’ll tell you exactly what it is and what to do about it—completely free. No strings. No catch. We’d rather earn your trust than make a sale.

✓ Free Assessment
✓ Honest Diagnosis
✓ Zero Obligation

Frequently Asked Questions

100% free. We come to your home, inspect the situation, and give you an honest diagnosis at no cost and no obligation. Even if it turns out to not be a waterproofing issue, you won’t owe us a thing.
We tell you exactly what we think it is—plumbing, grading, gutters, or something else—and point you in the right direction. You won’t waste money solving the wrong problem.
Our reputation is built on honesty. We’d rather walk away from a job than do unnecessary work. Check our 77+ five-star reviews—you’ll see homeowners we’ve helped without ever doing waterproofing work.
Central New Jersey & Eastern Pennsylvania—including Mercer, Monmouth, Somerset, Ocean, Middlesex, Hunterdon, Bucks, and Montgomery counties. Enter your ZIP code above to check.
Emergencies get same-day or next-day priority. Non-emergency assessments are usually scheduled within a few days. After submitting the form, you’ll pick a time that works for you.
Not for pressure—the opposite. What we find in a wet basement affects the entire home, and everyone who lives there deserves to hear the real diagnosis directly from us. No telephone game. No miscommunication.

Stop Guessing.
Get the Real Answer.

Whether it’s a $15,000 waterproofing job or a $400 plumber visit, we’ll tell you the truth—free of charge. No pressure. No games.

Serving Central New Jersey & Eastern Pennsylvania — limited slots available this week

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