Pool Clean-Up After a Hailstorm or Thunderstorm
Highveld summer storms arrive fast and leave a mess. In twenty minutes a late-afternoon thunderstorm can drop hail, strip leaves off every tree in the garden, wash soil off the flower beds and push the pool level up to the coping. By the next morning the water is often cloudy, the chlorine is low and the pump may not be running at all. Working through the clean-up in the right order gets the pool back quickly and avoids the green pool that so often follows a storm weekend.
Safety first
Before anything else, deal with the risks that have nothing to do with water clarity.
- Stay out of the pool during a storm. Lightning is a real danger to anyone in or near water. Wait until the storm has passed and the thunder has stopped for a good while before anyone swims or works at the pool.
- Do not touch electrical equipment that is wet or standing in water. If the pump, a heat pump, the chlorinator power supply or the lighting transformer has been flooded, or the pump room has water on the floor, leave it alone. Switch it off at the distribution board only if you can reach the board safely and dry, and call a qualified electrician before anything is switched back on.
- Keep children and pets away from a pool full of debris and broken branches until it has been cleared.
Check the distribution board after surges
Lightning and power surges often trip the earth leakage or the pool circuit breaker. If the pump is silent after a storm, look at the distribution board first.
If a breaker or the earth leakage has tripped, you can try resetting it once, provided nothing near the pool is wet or flooded. If it trips again straight away, stop. A repeat trip usually means moisture in a motor, a failed capacitor or a damaged cable, and resetting it over and over can make the damage worse. That is a job for an electrician or a pump technician, not another flick of the switch.
Check the timer too. Many timers lose their setting after a power cut and quietly run at the wrong hours, or not at all, for days afterwards.
Remove leaves, hail debris and silt
With the power sorted, clear the pool before running anything hard.
- Scoop floating leaves and twigs off the surface with a leaf net before they sink
- Lift heavy debris off the floor with a leaf rake or leaf canister, not the automatic cleaner, which will clog
- Empty the weir basket and the pump basket; after a big storm they may need emptying several times in the first day
- Rinse off soil and mud washed onto the paving so the next shower does not carry it straight back in
Hail itself melts harmlessly, but it shreds leaves into small pieces that pass through baskets and end up in the filter. Expect the filter to work hard for a day or two.
Check the pump before running it for long
Once the baskets are empty and the equipment is dry, start the pump and watch it. It should prime, fill the lid with water and run quietly. Signs that something was damaged include a loud hum with no movement, grinding or screeching, a burning smell, or a pump that runs for a few minutes and then cuts out. Switch off if you see any of these.
Surge damage to motors and capacitors is common after Highveld storms. If the pump is not behaving normally, our pool pump repairs page explains how we diagnose and repair them. A call-out to inspect or diagnose is R650. Deducted from your quote when you accept it.
If the water level is too high
A heavy storm can raise the level well above the middle of the weir mouth. When the water is too high the weir flap cannot skim the surface, so floating debris stays in the pool.
If your filter has a waste setting, you can lower the level by switching the pump off, setting the multiport valve to waste, and running the pump until the level is back to about halfway up the weir mouth. Switch off again before returning the valve to filter. Watch it the whole time; it is easy to take out more than you meant to. Make sure the waste water drains somewhere suitable and not into a neighbour's property.
Test and correct the water chemistry
Rain on the Highveld is naturally slightly acidic, and a storm carries dust, pollen and organic debris into the pool. Together they dilute the chlorine, use up what is left, and shift pH and alkalinity. This is why pools so often turn cloudy and then green a day or two after a storm.
Once the debris is out and the pump has circulated for a few hours, test the water.
- Check total alkalinity first, aiming for 80–120 ppm.
- Correct pH next, to 7.2–7.6.
- Then check free chlorine, which is likely to be well below the normal 1–3 ppm.
Correct alkalinity and pH before adding chlorine, because chlorine works far less well when pH is high. If the water is cloudy, our guide to cloudy pool water causes and fixes goes through the likely reasons in more detail.
Shock and filter longer
With the balance right, shock the pool with a dose sized to your volume, following the product label. Add it in the evening so it works overnight without the sun burning it off. Brush the walls, steps and floor to lift settled dust and algae so the chlorine and filter can reach it.
Then run the pump longer than normal for a few days. The filter has to remove the fine dust and shredded leaf material, and that needs time and plenty of water passing through it.
Backwash when the pressure tells you to
Storm debris fills a sand filter quickly. Keep an eye on the pressure gauge and backwash when it reads roughly 50–70 kPa above its clean reading, which after a big storm may come around much sooner than usual. Always switch the pump off before moving the multiport handle, then rinse after backwashing. If you want the full routine, see our step-by-step guide on how to backwash a sand filter.
Check the cover and solar heating panels
Hail can damage things you cannot see from the pool. Inspect them rather than assuming they came through.
- Pool covers. Look for tears, punctures and split seams, especially on bubble covers. Check the straps, anchors and any roller mechanism. A small tear grows quickly in the sun.
- Solar heating panels on the roof. Only inspect these if you can do so safely. Look for cracked or split tubes and leaking joints. Signs from the ground include water running off the roof when the solar pump is on, or wet patches under the panels. If you suspect a leak, turn the solar circuit off and have it checked.
- Heat pumps. Look at the fan guard and the fins for dents or debris, and leave it off if it was standing in water until it has been checked.
- Lights, fittings and the weir. Look for cracked lenses, loose fittings, and branches jammed against the weir.
When to call us
Most storm clean-ups are a few hours of netting, emptying baskets, testing and backwashing. Call for help when the pump will not run or keeps tripping the power, when there is damage to equipment, or when the water has turned green and is not clearing after a few days of correct readings and filtering.
A pool that has already gone green after a storm usually recovers without draining. Our green pool recovery is a fixed price by pool size, from R1,200 for pools up to 30,000 litres.
If storms keep leaving you with a clean-up job, a weekly pool maintenance plan means someone is checking the chemistry and equipment every week through the season, and weekly-plan clients do not pay the call-out fee.
WhatsApp us on 081 577 5051 with a photo of the pool and the equipment, and tell us what happened during the storm.