When the storms roll in and the backyard’s off-limits, it’s tempting to forget about the pool altogether. But winter in WA often brings steady rain. If you’re not keeping an eye on things, your pool could end up overflowing.
While pool use might drop off through winter, maintenance shouldn’t. Overflow can damage your surroundings, throw off your water balance, and cost you time and money later on in the year.
Let’s look at how to prevent your pool from overflowing in rain and why a few simple winter habits can make all the difference.
Why Pool Overflow Matters in Winter
Winter overflow might seem harmless at first, just a bit of extra water, right? But when left unmanaged, it can quietly create long-term issues.
Here’s what can happen:
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Excess water washes diluted chemicals into your garden, affecting soil and plants
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Rainwater overflow can seep under pavers or decking, softening the base and causing movement or sagging
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Continuous overflows can erode grout lines, damage coping, or lead to staining on pool surfaces
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Rebalancing a rain-diluted pool can take time and multiple chemicals, increasing costs
And if your pool is near structures like sheds, retaining walls or fencing, that water might be doing more damage than you realise.
Make Sure Your Pool Has a Way to Drain Excess Water
Every pool needs a way to handle overflow. If rain pushes the water level too high, it needs somewhere to go. Otherwise, it will spill out onto your paving, garden, or into nearby structures.
Start by checking what your pool already has:
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Overflow outlets or pipes (often built into the tile line or skimmer)
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Backwash line (in sand filter systems)
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Manually draining using the filter’s waste setting or a portable pump
If your pool doesn’t have a clear drainage option, think about using a submersible pump. It’s a simple tool that sits in the water and pumps excess water out to your garden or stormwater system when needed.
Tip: Avoid draining directly into your garden if you’ve recently added chemicals, especially chlorine, as it may affect plants.
Keep the Surrounding Drainage Clear
Clogged gutters, blocked stormwater drains, or poor landscaping can redirect rain straight into your pool area.
Ensure your external drainage system is in good condition to manage runoff and protect your paving or garden beds from water damage.
If water has nowhere to go, it will head straight for the lowest point, which might just be your pool.
Check Your Automatic Water Leveller
Some pools have automatic water levellers that conveniently maintain the water level—great in summer, but potentially problematic in winter. If your leveller is functioning correctly, it shouldn't cause issues. However, winter in Perth brings regular rainfall, meaning your pool will naturally fill up. During this time, the leveller should not be running at all.
If you notice it's still operating, this could signal a malfunction, likely due to a faulty float or sensor. Additionally, winter often brings leaf litter and other debris, which can block the overflow and lead to unintended overfilling. That’s why it’s important to not only check that your leveller is off, but also to inspect the overflow for any blockages.
If you're unsure or something seems off, call in a professional to assess and resolve the issue. You can always reactivate the leveller in spring when evaporation becomes a factor again.
Manage Your Pool Cover
A well-fitted cover is a smart investment, but during rain, it can collect puddles and debris.
Avoid letting heavy water weigh down the material, as this can force dirty water into the pool when it dips below the surface.
Tip: Secure the cover tightly around the edges to prevent it from sagging and dragging rainwater in.
Stay on Top of Water Chemistry
Even when not in use, your pool water needs to stay balanced. Overflow from rain can dilute sanitiser, shift pH levels, and reduce chlorine effectiveness.
Check your pool water every 2–4 weeks:
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Chlorine: 1–3 ppm
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pH: 7.2–7.6
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Alkalinity: 80–120 ppm
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Calcium hardness: 200–400 ppm
How Rain Affects Pool Water
Rainwater is naturally acidic, often with a pH below 6. It can:
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Lower your pool’s pH and alkalinity
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Introduce phosphates and organic matter that feed algae
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Dilute chlorine and make the sanitiser less effective
Test your pool after any major rainfall event. Adjusting levels early helps prevent green water and surface staining.
What You Can Do to Stop Your Pool from Overflowing This Winter
Avoiding overflow during wet winter weather is easier than you might think. Before heavy rain, lower the water level slightly and make sure your pool has a way to safely drain excess water. Keep the cover fitted and free of puddles, check that nearby drains are clear, and turn off your automatic water leveller if needed.
Even during winter, it's worth maintaining your pool water chemistry and running the pump each day to keep things circulating. After a heavy downpour, skim off debris, check your water level, and test your chemicals. These quick steps help you avoid overflow, protect your equipment, and keep your pool healthy throughout the colder months.
Keep It Dry, Balanced and Ready with Pool Assist
Knowing how to prevent your pool from overflowing in rain is just the start. Putting those steps into action is what protects your water quality, your equipment, and your backyard.
From adjusting water levels to checking overflow outlets and monitoring your system, a proactive winter pool maintenance schedule can save you time, money, and hassle in the months ahead.
At Pool Assist, we offer expert seasonal servicing across Perth and WA to help you stay ahead of winter weather.
Book your pool service today and prevent overflow before it becomes a problem.