Know Your Plumbing Fixtures

People take plumbing fixtures for granted all the time. Indeed, plumbing fixtures are quite reliable for the most part, justifying such an attitude. On the other hand, when something goes wrong with faucets, toilets, tubs, and traps, ignorance about them requires a call to the plumber. And because these problems are usually not that difficult to repair, the average homeowner can save the cost of expensive service calls by learning how his fixtures work and how to handle remedies himself.

Plumbing fixtures include sinks, tubs, showers, toilets, and bidets. Traps are part of all of these and merit special consideration. Common fixture problems are leaks, drips, damage, issues arising from faulty installation, and cross connections. Traps have their own set of concerns. In the rest of this article we will review all types and defects in more detail.

Sinks, tubs, and bidets all have faucets and temperature controls combined with some kind of basin or container (the actual fixture) that drains through a trap. Showers not combined with tubs also exhibit faucets and controls, but they lack a basin and the (virtually inaccessible) trap is hidden below a floor drain. Much of the plumbing for showers and tubs is difficult to access, lying behind sheet rock. Toilets have built-in traps but no faucets or associated parts.

Faucet parts eventually wear out, resulting in leaks, drips, or cracks; they commonly need to be replaced. This can at first seem daunting because of the overwhelming number of choices to make. But if one approaches the task systematically, replacing faucet parts becomes straightforward. Start with the basic functionality (kitchen, bathroom, pot filler, etc.) and be sure to match the mounting characteristics to the existing configuration. After that, choices come down to manufacturer, style, material, and color. Additionally, make sure you aren’t inadvertently introducing a cross connection (see below).

If plumbing fixtures have hot and cold controls reversed, the intake lines have to be reconnected to the correct valve or control. This is a bit more complicated than simply replacing washers or parts. However, many shower controls (and perhaps other fixtures) provide a mechanism for reversing hot and cold without having to reconnect intake lines.

A cross connection is a plumbing configuration that enables gray water to mix with and taint the water supply should negative pressure occur. Examples are faucet tips that drop below the basin high water line, hand-held showers left under tub water, and hoses attached to threaded laundry tub spouts. Dishwasher air gaps, washing machine standpipes, and hose bib backflow prevention devices are common methods used to break cross connections. When faucet parts are replaced, one should make sure there’s an air gap between the new spout end and the top of a filled basin.

Traps for plumbing fixtures are so named because their water seals prevent sewage fumes from entering the house. They are carefully designed to self-scour (replenish the water seal) with each use and to flow at the proper velocity. Too fast a flow tends to siphon away the water seal, while too slow a flow causes waste and debris to collect in the trap. The owner should check that all plumbing traps are the P type and that there is no double trapping (two traps in series). There are various ways to break a water seal, but one needn’t be concerned with them unless odors are detected.

Toilets are fixtures with self-contained traps and typically they require relatively little attention. It is a good idea to check for moisture accumulation behind and around the base and to see that intake lines aren’t leaking. In fact, this is good practice to follow periodically with all plumbing fixtures. Don’t hesitate to call a plumber with serious problems, but don’t be afraid to tackle minor defects on your own.