If you haven’t had to hire a plumber lately, you may not know how much it costs to have one come out and fix a problem that was preventable. First-time homebuyers and new homeowners will really benefit from knowing what to do to prevent household water troubles.

The first thing you need to learn is where your outside water shutoff valve is. That way, if you have an indoor leak from a broken water line or a drip that won’t turn off, you can prevent possible water damage before you call the plumber.

There are also items you should never flush down the toilet. Don’t feel fooled by products like baby wipes, feminine products, facial tissues and makeup removal sheets, and clumpable cat litter that are advertised as flushable. They contain plastic fibers that could clog plumbing, so stick to toilet paper that doesn’t clog pipes. Don’t pour anything down the sink that isn’t water soluble, and that includes oils and damaging chemicals. Older plumbing has narrower pipes, and/or you may not have enough water pressure to send some items along their way.

Waste disposals can pulverize a lot more foods than in the past, but you’re much safer avoiding feeding them anything fibrous such as banana peels, breads or fruits with seeds, starchy foods like potato skins, or foods with nuts. Run water as you put items in the disposal and give them enough time to grind thoroughly. Stuff a sliced lemon down the neck for freshness.