What I have learned about plumbing includes this interesting fact: water pipes aren’t the only ones that are plumbed, gas lines are plumbed too.
Your house may or may not have gas available to it. If you do have a gas line in your house, it is a relatively inexpensive matter to have a plumber hook it up to a gas furnace, a gas stove, or a gas log in a fireplace. You shouldn’t attempt to do it yourself unless you are thoroughly competent in the procedures involved, because gas leaks are highly explosive. Natural gas has no odor of its own, but the gas company adds a chemical to it to give it a strong, tell-tale scent. If you ever smell gas in your house you should shut the gas of at the main (make sure you know how to do this) and exit the house immediately, leaving the door open behind you to help vent gas out of the building. Then call the gas company.
On to water pipes. Unless you live in an extremely old house with no updates, you have indoor plumbing. Somewhere between the street and the place the water line enters your house, the water company’s responsibility for the pipe’s well being ends and your responsibility for it begins. This is important in three situations: (1) when you are digging on your property, to make sure you don’t damage the water main, (2) when tree roots have grown into and damaged the lines entering or exiting your house, and (3) when pipes freeze in cold weather. I only have personal experience with issue (3).
Usually the point at which you become responsible for the pipe is where it actually enters your house, and at that point you can take steps to prevent your pipes from freezing. Only pipes that run along outside walls are at risk, because the inside of your house is heated. When you move into a new house, make sure you know where the water lines are running. Find the point where the main enters your house, and take note of where all the sinks, toilets, tubs, showers, and washing machine hookups are. If any of these are on an outside wall, you may want to wrap the water lines with insulation, leave the cabinets they run inside open at night to let warm air from the house circulate better, or (worst case scenario) let the tap drip overnight to keep un-frozen water running through the pipe. If a pipe inside your house freezes, the expanding water will damage the pipe and when it thaws later you will have a water leak. The leak will be your problem.
It is possible for the pipes to freeze outside of your house, where you are not responsible for them. If this happens, you will wake up one cold morning with no running water. You should call the water company to tell them. They will send someone out who… here my exact knowledge fails me, but this person has a machine that they attach to the main outside your house which, I think, runs electric current through it and heats it up, removing the frozen blockage.
You want to treat your pipes kindly. Drains require especial care, because things other than water go down them and these things can stop them up. If leftover cooking fat is the kind that turns solid when it gets cold (butter, Crisco, lard, and bacon and beef drippings are all in this category) then DO NOT put it down your sink drain, as it will adhere to the pipes and over time cause a clog. My method is to let the fat cool in the pan, then pry it into the trash with a spatula. You can soak it up with paper towels, too, or if you’re a certain kind of hard core foodie you can keep it for more cooking later.
Other things can cause problems with drains, especially if you have an automatic disposal in your kitchen sink and therefore are less careful about what goes down it. One especial danger is things that have a fine, sand-like quality. These can compact in the pipe–especially where it bends–and clog the pipe. Egg shells and coffee grinds are the two often-named culprits for this, and I can personally attest to coffee grounds causing problems.
If you have an automatic disposal, read the instruction manual for it. Some say that grinding small bones is good for the disposal blades because it cleans them off, while others say they will damage the blades. Putting some ice cubes down the disposal periodically is definitely a good idea. Putting citrus peels down the disposal can help the drain to smell better.
If you do not have an automatic disposal in your kitchen sink, then you need to keep a trap in the drain to catch bits of food. When you are done using the sink you empty the trap into the trash.
Bathroom drains are apt to clog with hair and soap scum. Put a hairpin turn at the end of a piece of wire about 12″ long. When a drain begins to run slowly, remove the stopper (you will have to figure out how yourself, as there are many stopper mechanisms and they all come apart differently) and use the wire to physically remove most of the clog. You may find it necessary to use a chemical to further unclog your drain after doing this, but you probably won’t. Go easy on these unclogging chemicals because they are bad for your pipes.
A good routine for keeping drains fresh and running smoothly is to shake a good amount of baking soda into the drain, let it sit for several minutes, pour some white vinegar down the drain and let it sit for several minutes, then pour a kettleful of boiling water down the drain. This will help to break down greasy buildup and deodorize. Pouring some bleach water down a drain periodically couldn’t possibly hurt, either.
Your drains might run to a city sewer system or they might run to a septic system. If you have a septic system you need to know how to maintain it, which includes a knowledge of what chemicals you cannot put down your drains.
Your water may come from a city supply or may come from your own well. Again, make sure you know how to maintain your well if you have one.
Many houses used to have a cistern to supply water to them. In these systems water would run off the roof into the gutters, then into a holding tank in the yard or the basement, and this was the water for the house. I would guess that the number of houses that are still using cisterns instead of wells is vanishingly rare, but I don’t have any statistics to cite.
If the water in your area is extremely hard you may wish to install a water softener (or you might already have one). Old water softeners needed to have bags of salt pellets poured into them periodically, but I believe that newer versions use silica beads and need less maintenance. Extremely hard water will leave rust stains on your plumbing fixtures and cause soaps and detergents to be less effective. Over-softened water will make it hard to rinse soaps and detergents away. It also tastes bad compared to slightly hard water. My own preference is to avoid a water softener unless the water is so bad that it leaves rust stains.
Low-flow plumbing fixtures are environmentally responsible but come with some drawbacks. A faucet or shower head can be fitted with a device that reduces the amount of water that flows through it without affecting the water pressure. This results in reduced water usage. It can also take longer to rinse shampoo out of your hair in the shower, and it will definitely take longer to fill pots and glasses from such a tap. If you are interested in one of these devices, try it and see if you like it. You may not notice the difference. Low-flow toilets used to flush with less force because they were sucking less water down with each flush. As a result, it could take two or three flushes to empty the bowl. New toilets may use less water and also flush with decent force, I don’t have any information about that (our house still has the toilets that were installed in 1974).
The width of the drain the toilet flushes into determines how liable the toilet is to clog. If you are building or renovating, it is worthwhile to know what diameter drain is being put in.
A toilet sits on top of a wax ring that prevents leaks out the bottom. The wax can compress and dry out over time. It is probably worth replacing this ring every ten years or so.
Finally, a flush toilet is a simple mechanism, and if the pipes are sound and clear it cannot “break” in any way that you cannot fix by taking the top off the tank and fiddling with the mechanism. If your toilet stops flushing, take a few minutes to learn about the mechanism on the internet, and fix it yourself.
Shower heads are almost ubiquitous in the United States. An American feels riotous when faced with a bathtub that doesn’t have one. Many older houses have a shower head that is placed too low to get your head under. My explanation for this is that people use to wash their hair far less frequently than they do now, and when they did wash it the job was done in a sink–so shower heads were fixed low to keep hair dry. I find that a hand shower is more useful than a fixed shower head. You can more easily bathe small children with one, you can rinse the whole shower surround after scrubbing it, you can spray sand or grass clippings off of just your lower legs. Hand showers are either attached to a bar on which they can slide up and down, or to a hose, and they then have a holder to fit into somewhere. Many cheap hand showers come with a plastic hose that will crack after a year or two. You can buy a metal hose to replace it without buying a whole new shower head.
And that, dear readers, is all I feel like writing about plumbing right now.