Simple tasks such as adjusting settings or clearing a safe, accessible area may be suitable for a homeowner, but installing, disconnecting or repairing a hot water system generally requires a licensed plumber. Gas and electrical connections must be handled by appropriately licensed tradespeople, and plumbing work may require permits or compliance checks. Incorrect work can cause leaks, scalding, electric shock, gas leaks or property damage. For safety and warranty reasons, check the manufacturer’s instructions and get advice from a licensed plumber before deciding whether any DIY work is appropriate.