The plumber is highly skilled and equipped to address a wide variety
issues that occur in both input and output plumbing systems. The plumber
prefers being called to solve major problems, those requiring his
extensive training, and would just as soon let the layman tackle minor
problems. Therefore, it is worth the homeowner's effort to learn how to
distinguish tasks that he can do from those better left to the
professional plumber. It could also save significant expense.
You, the amateur plumber, must first understand how all of the plumbing in your house functions. We can categorize it into five systems: service, supply, drain, waste, and vent. The service system is what connects your house to the water source, which is typically provided by the city. The supply system distributes incoming potable water throughout the house. Drainage systems empty plumbing fixtures while preventing sewer fumes from entering the house. Waste plumbing connects the drainage system with septic tanks or public sewers, while vents are designed to equalize air pressure in both the drain and waste systems to assure proper functioning and to prevent backflow.
A plumber originally installed piping for all five of these systems when your house was built. A plumber also hooked up the appliances that use water, namely, the water heater, dishwasher, washing machine, and sometimes refrigerator or even dryer. The plumber also took precautions to avoid all cross connections, or possible ways for tainted water to get back into the water supply should negative pressure occur. Of course, piping and appliances get replaced from time to time due to wear and other reasons, and habitual use of fixtures can change. Thus it behooves the amateur plumber to periodically reassess his plumbing systems.
Start with the water heater. Check its age and consider replacing it (a job best left to the professional plumber) in the near future if it's older than eight to twelve years. Make sure the thermostat is set so that your hottest water is no more than 120 degrees to avoid scalding. If it doesn't have a TPR valve or the valve isn't properly terminated (typically about six inches above the floor), call a plumber immediately, for this is a safety concern.
Now go through the kitchen and baths checking the location and operability of the shut-off valves. Fill the fixtures and then look underneath while they drain to check for leaks. Also note whether the faucet assembly leaks. Fixing these problems is something you can probably do yourself rather than call a plumber. If you know or suspect that some faucets have been replaced since the house was built, make sure the spout tip is higher than the basin overflow level; otherwise, you have a cross connection. To remedy this, replacing the faucet yourself or hiring a plumber depends on your comfort level.