Michele, this is a common problem, especially from 2 to 6 years of age, during children's transition to toilet training and staying drying at night. The best strategy is to keep a waterproof mattress cover or mattress pad on your child's bed throughout this transition. Also keep a waterproof mattress pad on your own bed if your child likes to crawl into bed with you at night.
For dealing with this wet mattress episode, here are some tips from other experts and parents:
1. Soak up the excess urine: Soak up as much as possible of the urine on the mattress surface and what has penetrated inside, since whatever urine remains can continue to absorb moisture from the air and give off odors. If the stain is fresh and wet, apply a dry towel with lots of pressure to blot up the liquid. One parent suggests having the heaviest person in the house stand on the towel over the mattress. Continue to blot with fresh towels and pressure until no more liquid comes to the surface. This may take an hour. If the urine stain is already dry, start on the next step.
2. Apply 3 percent hydrogen peroxide: Saturate the stained area with liquid hydrogen peroxide. Leave it on for five minutes. Repeat procedure number one. (Note: hydrogen peroxide may bleach the mattress.)
3. Apply bicarbonate of soda or baking soda: Pour dry baking soda on the mattress and rub it in gently with a soft brush or firm sponge. Leave it on overnight. Vacuum off the dry powder the next day.
4. Dry the mattress fully before sleeping on it: Set it out in the sun for a day if possible. Alternatively, lay the mattress on its side with a fan blowing on it, or use a hair dryer.
5. Flip the mattress over when you replace it: Use the clean and unstained side of the mattress for sleeping.
Parents have also had success cleaning the mattress with dish detergent, vinegar or borax. You can also try using a wet vacuum instead of blotting the liquid with towels. If none of the cleaning strategies works, you may need to buy a new mattress.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.