If you notice a sudden increase in your water bill that does not correspond to an increase in the amount of water you know you were using in the house, you probably have a leak somewhere in your system. Without proper experience and diagnostic equipment, you will have a hard time pinpointing the source of the leak on your own. Your best bet is to call an experienced plumber who can inspect your whole plumbing system easily and figure out where the leak is and what to do about it.
Particularly if you live in an area with very harsh winters, freezing pipes can be a big issue. In order to prevent your pipes from freezing, you should turn off all outside faucets, disconnect the hoses attached to these faucets and drain the excess water from the system. Finally, wrap the faucets and outlets with dry cloth to further insulate them from the cold.
A bad smell coming from your garbage disposal is a common problem, but luckily it is usually easy to fix. The smell is the result of the buildup of food residue on the blades and in the garbage disposal chamber. A good deep cleaning is often all that is required to get rid of the smell. Before you start, make sure that all power to the unit is completely cut off. You do not want anyone accidentally flipping the switch and turning on the unit while you are working on it.
Next, take out the blades carefully and thoroughly wash them. You can also scrub out the inside chamber so that you are sure there is no residue left there. However, be sure not to use any harsh chemical cleaners, as these can damage the inner workings of the machine. Instead, use biodegradable soaps or natural cleaning agents like vinegar and baking soda to get the job done. Once you have thoroughly cleaned out your garbage disposal, you can help keep odors from coming back by periodically putting half a lemon and some baking soda down it and running it.
If your plumbing has never been inspected or you do not know when the last inspection took place, it is a good idea to have it done as soon as possible. Depending on your particular circumstances and the overall state of your plumbing system, a professional plumber can make recommendations about how often the process should be repeated.
If you live on a property with a lot of trees, for instance, you may need to have your plumbing lines inspected more often because of the chance that roots could begin to infiltrate the system. However, if there are no extenuating circumstances and your plumbing is otherwise in good shape, you could probably wait longer between inspections. In general, though, a plumbing system should be inspected annually.
A white buildup around your shower head and faucets is most likely mineral deposits that settle out from your water and accumulate over time. These can be cleaned off easily enough by soaking the fixture in vinegar overnight and then thoroughly scrubbing it. But that will not keep the problem from recurring. If your problem is severe or you would like to avoid future occurrences, you may want to look into having a water softener installed that can take those minerals out of your water before it reaches your taps.