Dangers of Salt Water Pools: Which Ones Are Real

The real dangers of salt water pools are mostly to your property and equipment, not your body. Salt water corrodes metal, wears plaster, spalls unsealed stone and slowly uses up the salt cell. Most of the health scares trace back to chloramines, which any chlorine pool can have, or to claims our sources do not support. Here is the truth about salt water pools, sorted into real, overstated and false.

This page sits under our salt water pools hub. If you are still deciding between systems, start with salt water pool vs chlorine.

Real: metal parts corrode and plaster wears faster

River Pools lists metal parts that corrode and salt that wears plaster faster on concrete pools among the cons of a salt system. Keep in mind that River Pools builds fiberglass pools, so the plaster point comes from a company that sells the alternative. It is a real concern, but the source gives no rate of wear, and neither will we.

Real: unsealed stone around the pool can spall

Salt water also works on the deck. Travertine Mart describes efflorescence, leeching and spalling, which happens when “salt water crystals are trapped beneath the surface of the stone”. In its example, unsealed natural travertine coping showed spalling after 2 years of daily exposure, and an impregnating sealer gave reasonable protection for 5 to 10 years. Travertine Mart sells travertine, not sealer. Our guide to sealing concrete around a salt pool covers the deck side.

Real: the salt cell is a part that wears out

The cell is a consumable. River Pools puts a cell’s life at 3 to 7 years, with replacement at $700 to $1,100, and the control board on a similar 3 to 7 year clock at $500 to $900. Spread over its life, the cell alone costs $700 / 7 = $100 a year at best and $1,100 / 3 = about $367 a year at worst. See how long a salt cell lasts and the salt cell hub for what shortens that clock.

One thing makes cell problems easy to misread. The generator has no salt sensor. Orenda explains that the cell reads conductivity, not salt. So scale, plate wear or cold water can move the salt number on the panel while no salt has moved. Test the water before you dump in more salt.

Real: converting may void a warranty

Leslie’s warns that converting “may void the warranty from the manufacturer or your pool builder”. Read your warranty before you convert a pool to salt water, not after.

Overstated: salt pools hurt your skin and eyes

Red eyes and itchy skin after swimming are real, but salt is not the likely cause. The CDC says chlorine combines with pee, sweat, dirt, skin cells and makeup to form chloramines, and that “Swimmers can experience red and itchy eyes, skin irritation, and rashes.” Chloramines irritate skin, eyes and the respiratory tract, particularly indoors. That can happen in any chlorinated pool, salt or not.

If you or your kids came out itchy, our page on a rash from a salt water pool separates the three things people usually mean.

False: a salt pool is chlorine free

A salt pool is a chlorine pool. The generator turns dissolved salt into chlorine in the cell. Leslie’s counts salt chlorinators as one of three types of pool chlorinator, and Trouble Free Pool sets a minimum free chlorine level for salt pools just as it does for manually chlorinated ones.

The “no chlorine smell” claim needs correcting too. River Pools lists “No chlorine smell” as a salt pool advantage. The CDC says that if you smell “chlorine,” you are probably smelling chloramines. A well-run salt pool smells less for the same reason a well-run chlorine pool does. A salt pool that smells needs more chlorine, not less. More on that in why a salt pool smells like chlorine.

False: it is like swimming in the ocean

NOAA says seawater averages about 35 parts per thousand, which is about 35,000 ppm. Hayward’s manual gives 3,200 ppm as the ideal salt level. A pool at 3,200 ppm is about 9% as salty as the ocean. It does not taste, float or sting like the sea.

Swallowing pool water and sodium

People ask whether swallowing salt pool water is bad for them. Our sources do not publish any evidence about the health effects of salt pool water on people, so we have nothing sourced to tell you and we will not speculate. The NOAA comparison above is only a sense of scale, not a safety finding. If sodium is a medical concern for you, that question belongs with your doctor.

Dogs

Dogs are a separate question with a clearer answer. Swimming is generally fine. Drinking is the concern: Hill’s Pet says that with salt water pools, “too much of it can still be bad for your dog (and potentially give them salt water poisoning).” Our full answer to can dogs swim in salt water pools covers symptoms and prevention.

The risk nobody talks about: ignored chemistry

A salt system makes chlorine automatically, so owners stop testing. That is where a real risk to swimmers comes from: too little chlorine.

Trouble Free Pool puts the minimum free chlorine for a salt pool at about CYA x 5%. With stabilizer at 50 ppm, the top of Hayward’s range, that floor is 50 x 0.05 = 2.5 ppm. A pool reading 1 ppm with 50 ppm stabilizer is under its floor, even though 1 ppm might look fine on a generic chart. Our best range of CYA for a salt pool and CYA chlorine chart walk through the numbers.

The second trap is the boost button. In The Swim says boost mode raises free chlorine only “a few clicks”, up to 5 to 7 ppm, and slowly. It is for superchlorinating, not shocking. In The Swim says to shock when chloramines reach 0.3 ppm or higher. See how to shock a salt water pool.

Every risk, sorted

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