Last Updated on October 4, 2026 by Umar Farooq
Rinse it in cold tap water the moment you take it off, before anything else. Then hand wash in cool water with a little mild detergent, rinse until the water runs clear, press the water out in a towel and dry it flat in the shade. No wringing, no dryer, and no chlorine bleach anywhere near it.
Every care guide puts rinsing somewhere in the middle of a list. It belongs at the top on its own, because it is not a cleaning step. It stops a chemical reaction already in progress.
The rinse is the repair, not the wash
A swimsuit leaving a pool carries chlorinated water in the fabric, and that water does not stop working when you get out. It sits in a warm rolled-up suit in a bag for the drive home and keeps going. Seawater behaves the same way. Billabong’s care page puts it plainly: “Salt from seawater and chemicals from pool water cause swim fabric to fade and weaken” (how to wash and dry swimsuits).
So the most valuable thing you can do costs thirty seconds and no equipment — rinse it under the cold tap, or in the shower you were going to take anyway. Which is the position this page will defend: a suit rinsed every time barely needs washing, and a suit never rinsed cannot be rescued by any cycle, detergent or soak.
What pool water does to the elastane
The stretch in a swimsuit comes from elastane, a polyurethane fibre, and chlorine attacks it directly. That is documented in the least likely place to find laundry advice: the background section of a patent for chlorine-resistant elastane, where the problem must be stated before the invention solves it.
Bayer’s filing, verbatim: “in swimming pools the water is frequently so strongly chlorinated for reasons of hygiene that the active-chlorine content usually amounts to between 0.5 and 3 ppm (parts per million) or even more. If polyurethane fibres are exposed to such an environment this can result in degradation or impairment of the physical properties of the fibres” (chlorine-resistant elastane fibres, US 5,969,008).
A fibre maker is saying normal pool water degrades the fibre. Not fades it, not stretches it — degrades it. The University of Georgia Extension lists the same property for spandex: “Damaged by chlorine bleach and heat”, with the instruction “Do not use bleach or detergents containing chlorine” (understand your fibers). Nobody bleaches a swimsuit on purpose. A pool does it dilute, every session.
How to wash a swimsuit by hand, in about four minutes
Hand washing wins here for a reason that has nothing to do with being precious about swimwear. A basin lets you control the temperature and apply almost no mechanical force, and mechanical force is what finishes off a knit already chemically stressed.
- Rinse in cold water until it stops smelling of pool.
- Fill a basin with cool water and a teaspoon of mild detergent. Maytag specifies one teaspoon per suit, less than most people pour.
- Submerge, swish and squeeze gently for a minute, then leave it ten to fifteen minutes.
- Rinse until the water runs clear. Residue stiffens the knit and attracts soil.
- Press, never wring. Lay it on a towel, roll, press. Dry flat in the shade.
The general technique is at how to hand wash clothes. One warning from Maytag: white vinegar is fine for pre-treating a stain, but “Never add vinegar directly to your washing machine.”
In the machine, if you are going to do it anyway
Plenty of people will not hand wash, and a flat refusal just means the suit goes in with the towels. Maytag’s machine route is sound: inside out, in a mesh bag, and “Swimsuits should be washed in a low spin, delicate cycle using cool or warm water and detergent” (how to wash and dry a swimsuit).
Low spin matters most and gets overridden most, because spin force stretches a wet knit against itself at the drum wall and a swimsuit is almost entirely knit and elastic (washer spin speed explained). The dryer is the one absolute. Maytag: “Avoid putting bathing suits in the dryer, as the heat can reduce elasticity and weaken the fabric.” Heat and chlorine damage the same component, so a suit that has had both ages twice as fast.
Sunscreen, sand and the concrete by the pool
Three things mark or wear a swimsuit that have nothing to do with washing. Sunscreen is the common one, and Billabong’s instruction is to spot-treat with baking soda or mild detergent before washing (how to get sunscreen stains out of clothes). Sand is mechanical: let the suit dry, shake it out, then rinse, because rinsing wet sand grinds it through the knit.
Then the one almost nobody mentions, from Billabong again: “rough or uneven surfaces like concrete by the pool or weathered lounge chairs can snag the fabric and cause it to pill.” Sitting down is a laundry decision.
FAQ
Should you wash a swimsuit after every use?
Rinse after every single use, without exception. A full wash with detergent can be less frequent, every few wears for casual use. The rinse is the non-negotiable part.
How do you get chlorine out of a swimsuit?
Cold fresh water, immediately and thoroughly. Rinse until no pool smell is left in the fabric. A fifteen-minute cold soak does more than any product sold for the purpose.
Can you put a bathing suit in the dryer?
No. Dryer heat reduces elasticity and weakens the fabric, attacking the component chlorine has already worked on. Roll it in a towel, then dry flat in the shade; direct sun fades the dye.
Why has my swimsuit gone baggy and see-through?
That is elastane that has lost its recovery, usually from chlorine and heat rather than wear, and it does not reverse. A suit that goes transparent wet is finished.
Rinse it in the shower you are already taking
The page reduces to one habit that costs nothing and happens before any laundry does. Get the chlorine or salt out at the pool and everything downstream is maintenance, not damage control.
A swimsuit is not ruined by swimming. It is ruined in the bag on the way home.
