Your Apple Watch is water resistant, but not waterproof. Water resistance isn't a permanent condition and may diminish over time. Apple Watch can't be rechecked or resealed for water resistance. TRhe water resistance of your Apple Watch may be affected by exposing the Apple Watch to soap or soapy water (for example, while showering or bathing).
When you start a swimming workout, your Apple Watch automatically locks the screen with Water Lock to avoid accidental taps. For other activities it is a good idea too manually turn on the water lock but it shouldn't be necessary for hand washing. If water splashes on to your Apple Watch, wipe it off with a nonabrasive, lint-free cloth. Don't use heat, compressed air, or sprays.
For more info, see:
About Apple Watch water resistance - Apple Support