Is Your Pool Ready for the Next Storm? How to Prevent the pool to Overflow

Pool Overflows After Heavy Rain and How to Lower Your Pool's Water Level

Has your pool ever overflowed during a heavy rainstorm, sending water into your yard, garden beds, or even toward your home?... or have you ever had to scramble before a storm to lower your pool’s water level to avoid a flood?

If you own a pool or are considering a home with one, especially if you plan to install one, this issue is more than an inconvenience. Pool overflow during storms can cause severe damage to your yard, your home’s foundation, and even your property’s long-term value. And while it’s a particularly common issue in older pools, new builds aren’t immune if drainage isn’t properly planned.

Here’s the good news: This problem is preventable.

In this article, you’ll learn:

• Why pools overflow during storms (especially older ones)
• What drainage problems often go unnoticed, until a downpour exposes them
• Why an overflow system isn’t a luxury, it’s a must
• Simple steps you can take to prepare before the next big storm
• What future homeowners and homebuyers should check for before purchasing a pool.

6 Reasons Older Pools Overflow During Storms

Many older pools were built when stormwater management standards and requirements were less standardized and less stringent than they are today. As a result, they often lack the core infrastructure to handle overflow during a major downpour. Here are some of the most common design flaws we see in older pools:

• No dedicated pool overflow drain: This means water has nowhere to discharge when the pool fills.
• Limited or nonexistent deck drains: Without these, rainwater can collect on the patio and flow into the pool or toward the house.
• Improper yard grading: Water may flow toward the pool, or worse, toward your home’s foundation.
• No drainage relief in retaining walls or slopes: Water gets trapped and redirected dangerously.
• Landscaping that disrupts original water flow: Changes made over the years can unintentionally trap or redirect water.
• Clogged or cracked underground drainage pipes due to root intrusion: A hidden hazard that dramatically reduces capacity during storms.

The result? When it rains heavily, these pools cannot handle the volume. Water spills over the coping and flows wherever gravity takes it.

Pool overflow is not a maintenance issue; it’s a design and drainage issue.

What Happens When Pool Water Has Nowhere to Go

When a pool overflows, the water doesn’t just disappear; it follows gravity and can cause a surprising amount of damage in a short time.

Common consequences include:

• Flooded lawns and flowerbeds
• Erosion of landscaping and mulch
• Water running toward crawlspaces or foundations
• Soil saturation around retaining walls or patios, leading to collapse or movement
• Long-term moisture issues that lower property value

Homes where the pool is elevated above the home, or where the yard slopes towards the house, are specially vulnerable.

without an overflow plan, even a short but intense storm can result in thousands of dollars in damage.

Does Your Pool Have an Overflow Drain? Here’s How to Tell

Many homeowners assume they have an overflow system, but most have never actually checked.

A proper pool overflow system:

• It is a dedicated outlet for excess water
• Automatically activates when water exceeds the set level (Gravity)
• Routes water into an approved stormwater outlet or discharge zone

What it’s not:

• A skimmer (removes surface debris, not excess volume)
• A backwash line (for cleaning DE filters exclusively, not overflow)
• Random deck drains that don’t connect to a functional outflow.

If you're unsure whether your pool has an overflow drain, get it evaluated, especially before storm season.

What to Do If You Don’t Have an Overflow System (Yet)

Not ready for a renovation? There are still temporary steps you can take to reduce the risk of overflow.

Short-term options include:

• Lowering your pool’s water level before a storm. This gives your pool room to absorb additional rainfall.
• Using a portable sump pump during storms to remove excess water from the pool or surrounding areas.
• Installing a manual discharge valve tied into your pool’s plumbing, but only if you have a proper outlet for it.

But be warned: Discharging pool water improperly can make flooding worse, mainly if it flows toward a neighbor’s property or back toward your home.

Always check where your discharge points flow. If the street level is higher than your yard, water may back up quickly.  Don't forget that months of dust and summer sprinkler debris runoff can significantly clog your drainage system, and that cleaning it before a storm is recommended.

Why Pool Drainage and Yard Drainage Must Work Together

Even the best pool overflow system can’t function well if your yard’s drainage isn’t supporting it.

Here’s where we often see problems:

• Yard drains that are too small or too few
• No drainage behind retaining walls
• Runoff from uphill areas flows toward the pool
• Surface water that has no defined exit path
• Clogged underground pipes from tree roots

If any part of your drainage system is underperforming, water will find its own way out, and it may not be where you want it.

How Tree Roots Cause Sudden Drainage Failures

The single most common drainage failure occurs when what's not visible fails in your yard.  Tree roots grow slowly but, over time, can entirely clog or damage underground drainage systems.

We see this all the time on older properties:

• Pipes are partially or fully blocked with root masses
• Joints between pipe sections separate or collapse
• Drainage capacity quietly disappears, until it’s too late

A drainage system can appear fine on the surface but fail catastrophically underground, especially during heavy rain.

Routine inspection and maintenance of underground lines is critical to storm prep and long-term protection.

Why Adding a Pool Overflow Is Not Optional, It’s Essential

Think of a pool overflow system like a safety valve, one you hope you won’t need, but absolutely want in place when you do.

Here’s why:

• It keeps water away from your foundation and crawl spaces
• It protects landscaping and hardscape from erosion
• It reduces pressure on yard drainage systems during storms
• It prevents unnecessary water discharge into neighboring properties
• It helps preserve your pool and your home’s long-term value

If you’re building a new pool, don’t treat overflow as an add-on. It’s part of a complete drainage strategy.

What Homebuyers and Future Pool Owners Should Ask Before Buying

If you’re buying a home with an existing pool, or planning to install one, make sure to ask the right questions about drainage.

Start with:

• Does the pool have a dedicated overflow system?
• Where does excess water go during a storm?
• How is the yard graded? Does water flow toward or away from the house?
• Are retaining walls or slopes equipped with drainage?
• Could underground lines be blocked by mature tree roots?

Ignoring these questions can lead to expensive surprises after you move in.

Storm Prep Checklist: 6 Steps to Get Ready for a Downpour

If a major storm is on the radar, here’s what every pool owner should do to reduce the risk of overflow and water damage:

1. Lower the Water Level

Use your pool pump or a siphon to reduce the water just below the skimmer. This gives your pool the capacity to absorb 4-5 inches of rainfall without immediately overflowing.

2. Check and Clear All Drains

Inspect and flush all deck drains, yard inlets, and grates near the pool and around the yard. Even partial clogs from leaves, mulch, or grass can slow drainage and increase the risk of flooding.

3. Trim Trees and Clear Greenery

High winds during storms can drop leaves, twigs, and branches into your yard and pool. Trim overhanging branches and remove nearby plant debris before the storm.

Why this matters: Wind-blown greenery can clog area drains or block overflow outlets, significantly reducing water flow during critical moments.

4. Clean Your Gutters

One of the most overlooked steps: clear out your roof gutters before a storm. Clogged gutters can overflow and spill debris, including leaves, twigs, and roof grit, directly into the yard or into your pool.

Without cleaning, roof runoff can carry months of accumulated debris into the pool, turning stormwater into a muddy mess.

5. Understand Where Your Gutters Drain

Many homes have roof gutters that are not connected to the yard’s drainage system. That means each gallon of roof runoff contributes to surface runoff, often overwhelming drains already struggling to keep up.

If your gutter downspouts discharge directly into the yard, driveway, or pool deck, consider installing extensions or redirecting them to proper outlets.

Even a well-designed yard drainage system can fail if it receives unexpected volume from roof runoff during a storm.

6. Prepare Backup Tools

Keep a sump pump handy in case pooling starts to form. A wet/dry shop vac and outdoor extension cords can also help quickly remove standing water. If your home sits downhill from your pool, consider keeping sandbags or water barriers in storage.

These proactive steps won’t replace a dedicated overflow system, but they can reduce damage, extend your response time, and give your pool and yard the best chance to handle the storm.

Protecting Your Pool, Yard, and Home Long-Term

After dealing with stormwater or pool overflow, it’s easy to feel frustrated, especially if damage could have been prevented. But now you understand what causes these issues and how to protect your home before the next big storm.

A pool overflow system, supported by solid yard drainage, is essential, not optional.

Your next step? Read our guide to residential drainage systems to see how yard grading, storm drains, and pipe design work together to protect your pool and your property.

At J Designs, we help homeowners create more innovative outdoor systems, ones that stand up to the weather, season after season.