Chemical cleaners generally should not be used to treat drains that are clogged to the point where water will not drain at all, or drains very slowly. If a chemical cleaner fails to open a clogged sink, tub or toilet, it can complicate other efforts to remove the blockage.
Chemical cleaners can be used to treat drains that are still open but working sluggishly and will sometimes restore them to full service.
Several types of chemical drain cleaners are available. Some contain caustic substances, mainly lye or acids, that are designed to literally eat through materials such as hair and grease that clog drains. These chemicals are dangerous and can cause serious injury if swallowed or splashed on skin or eyes.
Some chemical cleaners, intended for sluggish or open drains only, contain milder chemicals or use enzymes, which are relatively harmless to humans, to break up materials that accumulate in drains.
A force cup or plunger will work in many cases and should be part of every homeowner’s tool kit. Plungers, which have a rubber cup that is placed over the drain opening and worked up and down, must be used vigorously. Sometimes two or more workouts are needed.
Those who get poor results with a plunger can try other devices that can dislodge clogs with a forceful blast of compressed air or water. These devices are sold at some home centers, hardware stores and plumbing-supply outlets.
A plumber’s snake or drain auger, a flexible cable that is threaded into the drain to dislodge material, is another alternative.
Drains must sometimes be disassembled to remove clogs if other methods fail. If caustic chemical cleaners have been used in a drain, taking it apart can be a dangerous procedure even for skilled plumbers in surprise.
Having a semi-clogged sewer is especially dangerous during periods of heavy rain when the city sewer is backed up and water is pushed into the house. Often, the sewage cannot drain back down into the city system, prompting the homeowner to call to drain cleaning surprise service.