Can You Over-Chlorinate a Pool? (Here’s What Really Happens When You Do)
When it comes to keeping your pool clean, chlorine is the hero that fights off bacteria, algae, and all the things you don’t want floating around.
But as the saying goes — too much of a good thing can cause trouble.
So, can you over-chlorinate a pool?
Short answer: Absolutely. And when it happens, your water, your pool equipment, and even your swimmers can all pay the price.
Let’s dive into what “too much chlorine” really means, how to spot it, and how to fix it fast.
💭 What Does “Over-Chlorinated” Actually Mean?
Chlorine levels in a healthy pool should sit between 1–3 parts per million (ppm) for standard chlorine systems or 3–5 ppm for saltwater pools.
Once you creep much higher — especially past 5 ppm — you’re entering the danger zone.
At that point, chlorine stops being your friend and starts:
Bleaching swimsuits and pool liners
Drying out skin, hair, and eyes
Corroding metal fixtures
Throwing your pool’s chemistry completely off balance
Think of it like sunscreen — enough protects you, but too much doesn’t make you more protected, it just creates new problems.
🧪 How Over-Chlorination Happens
Even the most careful pool owners can end up with chlorine levels that spike. Common culprits include:
“Just one more scoop” syndrome: Adding extra chlorine “for good measure.”
Recent shock treatment: Chlorine spikes after shocking your pool (especially if swimmers jump in too soon).
Faulty automatic chlorinators: Stuck valves or incorrect settings can continuously feed chlorine.
Poor circulation: Uneven water movement causes concentrated chlorine pockets.
Low stabiliser (cyanuric acid) levels: Without enough CYA, chlorine burns off too quickly, tempting you to keep adding more.
👃 How to Tell If There’s Too Much Chlorine
You don’t always need a fancy lab test to know something’s off.
Here are the tell-tale signs:
Strong “chlorine” smell: That sharp odour isn’t clean water — it’s chloramines, formed when chlorine binds with sweat, sunscreen, and other contaminants.
Irritated eyes and skin: If everyone’s coming out looking like they’ve cried through a rom-com, it’s too strong.
Fading swimwear: Over-chlorinated water literally bleaches fabrics.
Cloudy or foamy water: Ironically, too much chlorine can destabilise your chemistry and make the water look worse.
For confirmation, use a test strip or digital water tester — if your chlorine levels are above 5 ppm, it’s time to act.
⚖️ How to Fix Too Much Chlorine
Don’t panic — it’s fixable!
Here are a few tried-and-true methods to bring your chlorine back down:
Let the sun do the work 🌞
UV rays naturally break down chlorine. Take the pool cover off and let the sunlight handle it for 1–2 days.Dilute with fresh water 💦
Drain a bit of pool water and top up with fresh water to lower the concentration.Stop adding chlorine
Turn off automatic feeders or salt chlorinators until your levels drop.Use a chlorine neutraliser
Products like sodium thiosulfate or hydrogen peroxide can quickly reduce chlorine — but use carefully and follow label instructions.Check stabiliser levels
Low cyanuric acid levels can make chlorine swing wildly. Bring it back to the ideal 30–50 ppm range to stabilise future readings.
⚠️ What Happens If You Swim in Over-Chlorinated Water
Occasional dips in slightly high chlorine probably won’t do serious harm — but regularly swimming in heavily chlorinated water can cause:
Skin rashes and itchiness
Red, burning eyes
Respiratory irritation
Dry hair and faded swimwear
It’s especially tough on kids and pets, who absorb more through their skin and are more sensitive to chemical exposure.
If in doubt — test before you dip.
💡 How to Prevent It Happening Again
Keeping your pool balanced long-term is easier than you think:
Test water regularly (2–3 times per week in summer)
Avoid “just in case” dosing — always test first
Schedule regular professional servicing to catch issues early
Check your chlorinator settings after storms or power outages
Maintain proper stabiliser levels year-round
🏁 The Bottom Line
Yes, you can over-chlorinate your pool — and while it’s a common mistake, it’s one that’s easy to avoid once you know the signs.
Keeping your chlorine in check not only makes your pool more comfortable to swim in but also protects your equipment and surfaces for years to come.
If you’re struggling to balance your pool chemistry or your water just never seems right, it might be time to call in the experts.
👉 Book a professional pool service today and we’ll get your water sparkling and perfectly balanced.