Rash From a Salt Water Pool: What Is Actually Causing It

The salt is the least likely cause of a rash from a salt water pool. A pool at 3,200 ppm is about 9% as salty as seawater, which NOAA puts at about 35 parts per thousand. Three other things get called “salt pool rash”: irritation from chlorine and chloramines, swimmer’s itch, and the rash the CDC describes in its hot tub guidance. They have different causes, and only one of them is likely to come from a well-run backyard pool.

This page is part of our salt water pools hub. For the broader list of what is and is not risky, see dangers of salt water pools.

Cause 1: chlorine and chloramine irritation

A salt pool is a chlorine pool. The cell makes chlorine from the salt, and that chlorine behaves the same way it does in any other pool. The CDC explains that chlorine combines with “pee, poop, sweat, dirt, skin cells, deodorant, and makeup that wash off swimmers’ bodies” to form chloramines, and that “Swimmers can experience red and itchy eyes, skin irritation, and rashes.” The CDC’s pool operation guidance adds that chloramines irritate skin, eyes and the respiratory tract when they off gas into the air, particularly indoors.

That is why the question of whether you can pee in a saltwater pool is not only about manners. Pee is on the CDC’s list of things that turn chlorine into chloramines.

Can you be allergic to a salt water pool?

Not to the chlorine, according to allergists. The American College of Allergy, Asthma and Immunology says “You can’t be allergic to chlorine, but you can be sensitive or have a reaction.” What people have is irritant dermatitis, not an allergy. ACAAI lists the skin signs as redness, tenderness, inflammation or itchiness where the water touched, a rash, scales or crust, and hives. It also notes that “Chlorine is also drying to the skin and can irritate existing dermatitis.” So if you already have eczema or dry skin, a pool can make it worse.

ACAAI adds that what looks like a chlorine allergy may actually be asthma or exercise-induced bronchoconstriction. Its advice is not to stop swimming, but to find and treat the cause with an allergist.

Cause 2: swimmer’s itch

Swimmer’s itch is an allergic reaction to microscopic parasites that infected snails release into fresh and salt water. People catch it in lakes, ponds and oceans, especially in shallow water near the shore. The CDC describes tingling, burning or itching and small reddish pimples that may blister, appearing within minutes to days, with itching that may last up to a week or more.

The key line for pool owners is this one from the CDC: “As long as your swimming pool is well maintained and chlorinated, there is no risk of swimmer’s itch.” The “salt water” in the CDC’s description means the ocean, not a salt chlorinated pool. If you have the signs of swimmer’s itch, think back to any lake, pond or beach trip in the days before. That is the likely source.

Cause 3: the CDC’s hot tub rash

This one needs careful framing. The CDC’s page on hot tub rash is hot tub guidance. It does not discuss pools, and we are not saying pools commonly cause it. It is here because it shows what happens when disinfectant runs low.

The CDC says hot tub rash is caused by “the germ Pseudomonas aeruginosa”. Contaminated water left on the skin causes “an itchy, red, and bumpy rash” and “pus-filled blisters around hair follicles.” It usually shows up a few days after time in a poorly maintained hot tub, and it is often worse where a swimsuit held contaminated water against the skin. The CDC’s hot tub guidance calls for chlorine of at least 3 parts per million.

The shared lesson for any pool, salt or not, is to keep the disinfectant up.

The three compared

How to prevent it

The CDC’s steps are simple. Rinse off in the shower for one minute before you get in, which the CDC says can remove most of the dirt on your body. That is less material for chlorine to turn into chloramines. After swimming, the CDC’s hot tub guidance says to remove your swimsuit and shower, which is sensible after any swim.

On the pool side, keep chlorine at the pool’s proper level. In a salt pool, “proper” depends on your stabilizer. Trouble Free Pool puts the salt pool minimum at about CYA x 5%, and our page on optimal chlorine levels shows how to set it. If the pool smells strongly of “chlorine,” that is usually chloramines, and it means the pool needs more chlorine, not less. Our page on why a salt pool smells like chlorine explains the fix. The salt cell hub covers keeping the generator producing.

Is a salt water pool good for your skin?

Here is what our sources support. A well-run pool with fewer chloramines is less irritating, because chloramines are what the CDC links to skin irritation and rashes. River Pools lists salt pools as gentler on eyes, skin and hair, but does not cite evidence for it, and a salt pool with low chlorine can build chloramines like any other.

Here is what they do not support: that the salt itself is good for your skin. None of our sources says so. We are not going to claim it.

When to see a doctor

A rash that blisters, spreads or lasts should be seen by a doctor. If you suspect you are sensitive to chlorine, ACAAI recommends seeing an allergist to find and treat the cause, rather than giving up swimming.

Where to go next