You may want to shower without a colostomy bag on the days when you are changing the pouch and with one on the other days — it is entirely up to you. Note that colostomy bags are waterproof so you don't need to take extra precautions when you wear one in the shower. If you are using colostomy bags with filters, then you should cover the filter with a protective sticker — this is usually included with the stoma bag. Waterproof shower covers for colostomy bags are also available and you may want to use them when showering at the gym or going for a swim in the pool, simply to conceal the contents of the pouch. While most ostomy bag covers and holders are machine-washable, shower covers should simply be hand-washed with cool or lukewarm water and left to air dry.