This article is brought to you by AskBobCarr.com — Maryland’s go-to source for honest drainage advice, foundation protection, and water-smart landscaping from Bob Carr and the TLC team.
After 30+ years of solving water problems, I’ve seen what works — and what really doesn’t. Some mistakes are obvious. Others are sneaky. But they all cost homeowners time, money, and stress.
Here are the 10 biggest drainage mistakes I see again and again — and what to do instead.
1. Ignoring the Slope Around the House
Mistake: The soil near the house is flat or sloped toward the foundation.
Fix: Make sure the soil drops at least 6 inches over the first 10 feet away from the house (5% slope).
Why it matters: Without that slope, water hangs around your foundation. That leads to seepage, crawl space humidity, and even long-term structural problems. We’ve seen houses where the concrete looked fine from the outside, but inside, there were cracks and rot from years of water sitting against the walls.
Real story: A family in Severn had a basement with musty smells and occasional seepage. The yard looked flat. We used a laser level and found the grade sloped back toward the house. We regraded, added a swale, and the basement dried out for good.
2. Short or Disconnected Downspouts
Mistake: Downspouts end too close to the house — or worse, have come apart underground.
Fix: Extend downspouts 10+ feet away and check underground piping for breaks.
Why it matters: One inch of rain on a 1,000 square foot roof = over 600 gallons of water. If your downspouts dump that right at the base of your house, you’re flooding your own foundation.
Pro tip: Check your downspouts every season. Make sure the elbows are connected, and there are no leaks where pipe sections meet.
3. Burying Corrugated Drain Pipe
Mistake: Using thin, flexible pipe that crushes, clogs, or collapses.
Fix: Use smooth-walled PVC or SDR-35 pipe with cleanouts every 50–75 feet.
Why it matters: Corrugated pipe may be cheap and easy to install, but it fails fast. Tree roots get inside. Sediment builds up. And because it’s ribbed inside, water flow slows and debris sticks.
What we do: We install smooth 4” drainpipe, properly sloped, with access points for cleaning. That system can last 20+ years.
4. Believing Mulch Will Soak Up the Water
Mistake: Adding mulch to soggy beds thinking it’ll solve drainage.
Fix: Mulch floats. Fix the slope or install a drain first.
Why it matters: Mulch hides standing water but doesn’t eliminate it. When the mulch floats or shifts, you’re left with soggy roots and soil that never dries.
Smart landscaping: Always resolve grading and drainage first. THEN mulch and plant. Otherwise, your new landscape will suffer.
5. Installing French Drains Without Slope or Fabric
Mistake: Digging a trench with no pitch or filter fabric, then wondering why it backs up.
Fix: French drains need pitch (1–2%), gravel, and nonwoven fabric to stay clean.
Why it matters: A French drain without slope is just a muddy trench. And without fabric, fine soil clogs the gravel and pipe in a year or two.
What we recommend: Trench 12” deep, 6–8” wide, use clean gravel, wrap it in filter fabric, and provide a clear exit like a pop-up emitter or daylight drain.
6. Assuming Gutters Are Optional
Mistake: Skipping gutters or letting them overflow.
Fix: Capture every drop from the roof and direct it far from the house.
Why it matters: Gutters are your first line of defense. Without them, water falls directly onto the foundation zone. And even with gutters, clogged or overflowing systems still flood your property.
Maintenance tip: Clean gutters twice a year. Use guards if you have trees nearby, and always check that your downspouts discharge far enough from your home.
7. Ignoring Neighbor Runoff
Mistake: Not accounting for higher yards draining into yours.
Fix: Use swales, berms, or catch basins to redirect outside water.
Why it matters: Water doesn’t care about property lines. If your neighbor’s yard slopes into yours, you’ll take on their problem. We’ve helped homeowners defend against uphill runoff with natural-looking berms or swales that guide the flow without causing disputes.
Real case: In Edgewater, a homeowner blamed his soggy lawn on rain. Turns out his neighbor’s downspouts all drained into the same low spot. We added a swale and catch basin, and both yards improved.
8. Not Matching the Fix to the Problem
Mistake: Installing a dry well when you need a swale — or a French drain where water is pooling on top.
Fix: Match the solution to the water source (roof, surface, subsurface).
Why it matters: Each drainage tool has a purpose. Swales for surface water. French drains for underground seepage. Dry wells for isolated downspouts.
Our approach: We walk every yard, trace every puddle, and pick the system that matches the problem. No one-size-fits-all.
9. Letting Landscape Hide the Problem
Mistake: Burying drainage issues under plants, patios, or mulch.
Fix: Always fix the grade and flow before adding landscaping.
Why it matters: Once hardscape is in place, it’s 10x harder to fix the real issue. We’ve seen beautiful patios ripped up because water kept backing into basements.
Better approach: Solve water flow first. Then landscape with confidence.
10. Waiting Too Long to Fix It
Mistake: Hoping the puddles will go away or “it’s not that bad.”
Fix: Drainage issues get worse over time — and cost more to fix later.
What we see: – Water seeps into basements – Lawns drown and die – Mold creeps into crawl spaces
Early intervention saves thousands. A $3,000 swale today may prevent $20,000 in water damage next spring.
Bob’s rule: If you’ve got water standing more than 24 hours after rain, it’s time to act.
Bonus: How to Know Your Drainage Fix Is Working
After a storm: – No water near the foundation – No standing puddles on lawn – Sump pump doesn’t run nonstop – Basement or crawl space stays dry
Annual check: Walk the yard after 1” of rain. Look for pooling, soggy spots, or disconnected downspouts. The best fixes work silently — and make your yard usable again.
Final Thoughts From Bob
Smart drainage doesn’t start with a shovel. It starts with a plan. Let’s walk your yard together, find the real problems, and fix them for good.
I’m not interested in short-term patches. I want to solve it once, the right way, so you don’t have to worry every time it rains.
📞 Call (410) 721-2342 or request your custom drainage evaluation at AskBobCarr.com
Because great drainage isn’t just underground pipe — it’s peace of mind that lasts for years.