What To Do About Water Sitting On Your Wood Deck

It rained again last night, and now you’re staring at standing water on your wood deck. Maybe it’s pooling in the same spots every time. Maybe it’s starting to leave dark stains behind. You’ve spent time and money trying to keep your outdoor space looking nice, and now you’re wondering if all that moisture is going to lead to rot, mold, or worse, expensive repairs. 

It’s frustrating, especially when the weather finally warms up and you’re hoping to enjoy your deck without worrying about damage.

At Brush & Roll Painting, we’ve seen this issue more times than we can count. We’ve been working with homeowners in Omaha since 1996, helping them maintain and protect their wood decks. Pooling water isn’t just a cosmetic issue; it’s often a sign that something is off, whether it’s the way the deck was built, how it was maintained, or what kind of finish was used.

This article will explain why water sits on wood decks after it rains, what problems it can cause, and how you can fix or prevent it. By the end of reading this article, you’ll know how to spot early signs of water damage, what steps you can take to make sure your deck lasts, and when it might be time to get help. 

Why Is Water Pooling on Your Deck?

When you see standing water on your deck, it usually comes down to one (or more) of these common problems:

1. The Deck Boards Are Too Close Together

Wood needs room to breathe. When boards are installed without enough space between them, usually less than one-eighth of an inch, there’s nowhere for water to drain. That means even a quick summer storm can leave puddles behind that take hours or days to dry.

Over time, this standing water can:

• Soak into the wood and speed up rot
• Attract insects
• Cause mold or mildew to grow
• Leave dark water stains that don’t come out easily

Sometimes, boards are installed too tightly from the beginning. Other times, they swell over time due to moisture exposure and never fully contract back.

2. The Deck Isn’t Sloped Properly

Wood decks should have a slight slope, usually about a 1/8 inch drop per foot, so that rainwater runs off instead of collecting. If your deck is level, or worse, tilting inward, water won’t drain the way it’s supposed to.

This can happen if the deck was installed incorrectly or if parts of the frame have settled unevenly over the years.

3. Clogged Gaps or Debris

Leaves, dirt, and gunk can block the gaps between boards. If you notice that water is only pooling in a few spots, take a look—there might be compacted debris acting like a dam. This is especially common in the fall, when trees drop leaves that get wedged between boards and trap moisture.

4. Old or Worn-Out Deck Sealer

Even if the deck was sealed in the past, it might not be protected anymore. Sealer wears down over time, especially with Omaha’s mix of rain, snow, heat, and humidity. If your deck doesn’t repel water anymore, meaning water soaks in instead of beading on the surface, it’s more likely to develop water stains and long-term damage.

What Happens If You Ignore Standing Water on a Wood Deck?

Ignoring water that sits on your deck might not cause immediate problems, but over time, it can take a toll. Here’s what can happen:

Wood Rot

Wood that stays damp too long starts to break down. The structure becomes soft, spongy, and unsafe to walk on. Even pressure-treated wood can rot if water sits on it regularly.

Staining and Discoloration

Water stains often look like black or dark gray splotches. Once they set in, they’re tough to remove without sanding or replacing the board.

Mold and Mildew

Mold loves damp, shaded areas. If you notice a musty smell or slippery green or black patches, that’s a sign of mold or mildew, and it’s not just a surface problem. It can also cause health issues and make the deck dangerous to walk on when wet.

Warping or Splitting

Wet boards can swell, then shrink when they dry, causing warping and cracking. That can make your deck look uneven and make repairs more expensive down the line.

How to Fix the Problem (and Prevent It in the First Place)

Here’s what you can do if your deck is holding water—and how to keep it from happening again.

1. Check the Board Spacing

Look closely at the spacing between the deck boards. If they’re too tight or completely flush, that may be the root of your drainage issues.

Solution: If you’re handy, you may be able to pull a few boards and reinstall them with proper spacing. Otherwise, this may be something to bring up with a contractor or deck specialist. For new builds or repairs, make sure there's at least a 1/8 to 1/4 inch gap between each board.

2. Improve Drainage and Slope

Lay a level across your deck. If it doesn’t slope slightly away from the house, water will collect and settle.

Solution: This fix usually involves modifying the substructure. It might mean re-shimming joists, adjusting supports, or rebuilding part of the frame, something best left to a professional if you're not experienced with deck construction.

3. Clean Out Gaps and Surface

Use a putty knife or deck cleaning brush to clean between the boards. Pressure washing can also help remove grime, but use a fan tip and be careful not to gouge the wood.

Ongoing maintenance tip: Blow off leaves and debris with a leaf blower every week or two, especially during fall and spring. It only takes a few minutes and can save you hours of work (or hundreds in repairs) later.

4. Re-Seal the Deck

If water is no longer beading on your deck, the seal is gone. You can test this by sprinkling water on the boards; if it absorbs right away, it’s time to re-seal.

Solution: Use a high-quality deck stain or sealer that’s made for wood. Products vary, but many need to be reapplied every 3-5 years in our Nebraska climate.

We recommend using a penetrating oil-based or water-based semi-transparent stain, depending on the deck’s condition and the customer’s goals. The key is to clean the wood thoroughly, let it dry completely, and apply stain in the right conditions, not too hot, not too humid.

What If the Deck Already Has Water Damage?

If your deck already has rot, mold, or warped boards, it may not be a quick fix.

Here’s what to do:

• Soft spots or spongy boards likely need to be replaced. If the rot is localized, you may just need to swap out a few planks.
• Black stains can sometimes be removed with oxalic acid-based wood cleaners. But deep stains may require sanding.
  Mold and mildew should be scrubbed off with a deck cleaner designed for mold. Avoid bleach, which can damage the wood fibers.
• Loose or wobbly railings or steps can be a safety issue. These usually point to structural water damage underneath the surface and need to be inspected right away.

If you're not sure how bad the damage is, it’s worth having someone come take a look before the damage spreads or becomes a bigger liability.

How to Keep Your Deck Dry Year-Round

Omaha weather can throw a lot at your deck—snow in the winter, thunderstorms in the summer, and everything in between. Here are some practical ways to stay ahead of water damage:

• Inspect your deck twice a year (spring and fall) for signs of damage
• Clean debris regularly from between the boards and on the surface
• Re-seal every 2 to 3 years, or sooner if the finish wears off
• Trim nearby trees to let sunlight hit the deck, which helps it dry faster
• Use a deck cover or awning if your space stays damp most of the time

Deck Staining in Omaha, NE

If you’ve been dealing with standing water on your deck after it rains, you’re not alone, and now you know what to do. Whether the cause is poor spacing, slope issues, or worn-out stain, these are fixable problems. You’ve learned how to spot early warning signs of damage, what kind of maintenance will help, and how to know when it’s time to call in help.

At Brush & Roll Painting, we’ve helped Omaha homeowners protect and restore their wood decks for decades. We understand how important it is to get the job done right so your deck lasts through many more Nebraska seasons.

Click the button below to get a quote for deck staining or refinishing.

Not quite ready to start a project yet? Click the button below to use our deck staining pricing calculator to get an idea of what your project might cost.