Bathrooms are where most household accidents happen, and a number of plumbing decisions affect how safe and usable a bathroom is over time.
Water temperature is the most important. A tempering or thermostatic mixing valve limits the temperature delivered to bathroom outlets, which is what protects against scalding. This matters most for young children and older adults, whose skin burns at lower temperatures and in less time.
Tap style makes a practical difference. Lever handles need far less grip strength than traditional capstan taps and can be operated with a forearm or elbow, which helps anyone with reduced hand function.
A hobless or level entry shower removes a step, which reduces trip risk and makes access easier. It also depends on the floor being laid to an adequate fall, so it is a decision that belongs at design stage rather than afterwards.
Fixture heights, and provision for grab rails to be fixed into something solid, are worth deciding before walls are closed up rather than retrofitting later.
If a hot water system is leaking, making unusual noises, or delivering water hot enough to scald, switch it off at the isolation point if you can do so safely and call a licensed plumber. Tempering valves and pressure relief valves are not do it yourself items, and a failed relief valve can be dangerous.
