One of the biggest mistakes people make is putting food fat in the sink. It slides down easily enough at first, but when it cools, it becomes a lump of congealed mess which has to be forced down the line; and this means literally forced. Food fat is one of the most dangerous of the pipe enemies. The best way to dispose of fat is putting it in a heat-proof jar and contacting your trash company to find out the best way to dispose of the jar.
This may seem fairly obvious, but paint should never be put in any of your plumbing to be flushed or washed down the lines. Paint must be disposed of properly for environmental reaons and to keep your pipes safe. This will require a call to your hazardous waste department for your area, but it is well worth the call. Damaging sewer lines, pipes, and the water supply is very costly in many ways.
This one may also seem equally as obvious, but a major danger to plumbing is caulking material. Caulking of fixtures, sinks, showers, and tubs is necessary. It comes in water-soluble and non-soluble varieties, and neither can go down the lines. Keep a damp rag with you while caulking or a small bowl you do not plan to use again and fill it with water to wash your hands as you work. Again, please contact your local hazardous materials program to find out how to safely dispose of caulking residue.
This one may seem silly, however, if you have children, you may have observed your child putting pencil savings down the toilet. OK, it’s pretty much a guarantee you have seen this happen! Pencil shavings are small in size individually and will typically not be in large amounts. This does not make them any less of a threat. They have lead which is a major water contaminant and enough of any solid can become a problem.
Now, the next three are delicate in issue, but not even remotely delicate when it comes to plumbing. These are three of the biggest plumbing no-no’s; condoms, tampons, and pets, such as goldfish, small lizards, frogs, etc…The details as to how they can cause problems are not important, and might make you lose your appetite. Just know, if any one of these things gets stuck in the lines, you are looking at almost certainly having to call your plumber. The first two are trash items and the proper way to discard the remains of your pet is an animal control issue. Please contact your local office to find out what they recommend.
Note: Calls to your local waste collection and hazardous waste department and animal control are recommended, and may seem like an inconvenience, but each area has different rules for disposal, so the recommendations are not uniform. In Los Angeles county, 311 is an excellent resource to obtain the necessary contact numbers.