Waterproof Cosmetics — What Does "Waterproof" Really Mean?

"Waterproof" — one of the most misleading terms in cosmetics

When you see the word "waterproof" on a sunscreen, you naturally assume the product resists water. And technically that's not a lie — but it doesn't mean what most consumers think. No cosmetic is 100% resistant to water, sweat or friction. That's why the European Union introduced precise rules governing what manufacturers can (and cannot) claim on their packaging.

Water-resistant vs waterproof — the difference in EU regulations

The 2006 European Commission recommendation (2006/647/EC) on sunscreen products explicitly advises against using the term "waterproof" on SPF products, because it can imply complete, lasting protection in water — which is impossible.

Instead, the recommended term is "water-resistant", which communicates precisely: the product retains part of its UV protection after immersion in water, but not all of it and not forever. Find out more in our ingredient encyclopedia.

In practice:

• Water-resistant: The product retains at least 50% of its stated SPF after two 20-minute baths (40 minutes in water in total).
• Very water-resistant / extra water-resistant: The product retains at least 50% of its SPF after four 20-minute baths (80 minutes in water in total).
• Waterproof: A term discouraged in the EU — used mainly in the US market (FDA), but since 2011 the FDA has also restricted it.

How is the water resistance of SPF products tested?

The testing standard is based on the COLIPA (Cosmetics Europe) method, now harmonised with the ISO 16217 standard:

1. The product is applied to volunteers' skin at the standard dose (2 mg/cm²).
2. 15–30 minutes after application, the volunteers immerse themselves in a bath of water at 23–32°C.
3. They make moderate movements (simulating swimming) for 20 minutes.
4. They get out, air-dry (without towelling off) and repeat the immersion.
5. Once the cycles are complete, the SPF on the skin is measured and compared with the baseline value.

If the product retains ≥50% of its SPF after the required number of cycles, it can be labelled water-resistant. It's worth stressing: the test takes place under controlled conditions — gentle movements in a bathtub are nothing like diving through waves, playing on the beach or swimming hard.

Why is no filter truly waterproof?

UV filters — both chemical and mineral — settle on the surface of the skin and form a thin protective layer. Water, sweat, sand and friction (a towel, clothing) physically remove that layer. Even the best film-forming polymers (e.g. VP/Hexadecene Copolymer, Acrylates Copolymer) extend durability, but they don't make a product indestructible.

Other factors that reduce protection:

• Sweat: Continuous perspiration washes filters away even without contact with water.
• Friction: Towelling off after a swim removes a significant amount of the product.
• Time: Chemical filters photodegrade — they lose effectiveness under UV exposure, regardless of contact with water.
• Insufficient dose: Most people apply 25–50% of the recommended amount, which drastically reduces the actual SPF.

You'll find more on proper UV protection in our guide SPF in creams — how much do you really need?

Reapplication rules — the golden rule

Regardless of the stated water resistance, dermatological recommendations are unequivocal:

• Reapply every 2 hours while in the sun.
• Immediately after a swim — even if the product is water-resistant.
• After towelling off — friction removes more filter than water alone.
• After heavy sweating — a workout, a hike, physical labour.

This rule applies to both chemical and mineral filters. Mineral filters (zinc oxide, titanium dioxide) don't photodegrade, but they do come off mechanically — friction and water wash them away just the same.

What to look for when choosing a water-resistant SPF?

When choosing a sunscreen for the beach or the pool, pay attention to a few things:

• A "water-resistant" claim with a stated duration (40 min or 80 min).
• Film-forming polymers on the INCI list (VP/Hexadecene Copolymer, Acrylates/C10-30 Alkyl Acrylate Crosspolymer) — they improve adhesion to the skin.
• Broad UVA/UVB spectrum — a "Broad Spectrum" label or the UVA logo in a circle.
• SPF 30 or higher — in beach conditions, a lower SPF offers minimal protection once it washes off.

Compare filter formulas in the PurScore search engine — you can check which filters and polymers your product contains.

Summary — common sense instead of magic

The term "waterproof" in cosmetics means: the product stays on the skin better than average, but it isn't indestructible. EU regulations rightly restrict the use of the term "waterproof" — no product offers 100% protection in water.

Practical advice: treat every exit from the water as a moment to reapply. It's the only truly effective sun protection strategy.