My water tank hasn't been cleaned in years — is this a health risk?

Yes, this is a genuine health concern. Dubai Municipality requires water tanks to be cleaned by licensed companies every 6 months — this isn't a guideline, it's a regulation. An uncleaned tank in Dubai's heat can harbour bacteria including Legionella, which causes Legionnaires' disease. The slightly off taste you're noticing is a warning sign. Responsibility: The building's main storage tank is the landlord's or building management's responsibility to clean and maintain. Your individual apartment may also have a smaller storage tank — ask your building management whether this is separate and whose responsibility it is. Action: Raise this in writing with your building management immediately, referencing Dubai Municipality's 6-month cleaning requirement. If they don't act, you can report them to Dubai Municipality. For your own peace of mind, run your taps for 2–3 minutes before drinking while this is being resolved and use filtered water.