It takes time to become a good plumber, i.e., he has to spend more time for his career to be successful. There are many areas where a water heater like "wet only plumber" & in "Gas Industries". In the first type work is done in homes such as fitting bathroom, sprinkler system. Second type is very sensitive. To work in a gas industry one has to first achieve Council of Registered Gas Installer Certificate. Some plumbers normally work in domestic areas such as leaky taps & blocked sinks etc. Normally whatever field a plumber chooses the basic thing he must know is Water Regulations & Building Regulation.
85. Know your IRPCS International Rules for Preventing Collisions at Sea and be aware of how you should approach water line repair or cross a traffic separation scheme TSS).
You don't want to be paying your plumber to clear the area before they start work particularly if you are paying an hourly rate. Empty cupboards and make sure there is nothing that may cost the plumber time and you money gaining access to the job.
Depending on your repair job you might need a bucket that will fit below the sink trap, as well as some rags and newspaper. Masking tape is useful for labeling and for wrapping around the heads of the wrench to protect your chrome tap handles. Rubber gloves are recommended, particularly when working with the toilet, but there are greases and glues that you may not want on your hands.
Be certain that the bathroom exhaust fan vents to the outdoors, not into the house or attic. If the exterior vent dampers don't operate properly or water line repair don't seat well have them fixed or replaced.
People who own rental properties are great ones to give you information. With all of the service people needed for maintenance on their units, they typically know who to call and what level of work they perform. Most property owners will be more than happy to give you the information you seek. In fact, they were probably in your shoes at one time.
The plumber you hire does not normally do heating but will do hot water heating or in floor heating in the house. Some places you can use the water heater for both domestic hot water and for in floor heating if the heating is a secondary heat. Check with your local plumbing codes on this to be clear.