Why does my bathroom sink drain so slowly?

[Johnny]

Why does my bathroom sink drain so slowly? I removed the piping below and it was clear. Meanwhile, the tub and toilet drain normally.

Also, how much could it cost to repair the sink drain problem?

[home improvement guy]

It's quite likely you're experiencing a partial clog comprised of hair and soap scum, but there are other possible causes, including:

- Old piping deteriorating from within.

- An object that went down the drain and is stuck in the pipe.

- A problem with your main drain line, such as intruding roots.

A hair clog can be the likeliest culprit.

Hair from brushing, shaving or beard-trimming goes down the drain, becomes matted and forms bird-nest-like snarls that then attract soap bits and other items.

An on-site inspection can determine for certain the cause of a slow or stopped sink drain. However, I suggest a few actions you can take before calling a plumber:

- Use a plunger; cover the sink overflow hole with duct tape.

- Use a plumbing snake or auger. You said the pipe below the sink is clear; therefore, the clog may reside in the short horizontal run from the trap to the wall. Instead of a snake, you could try a rag twisted around the end of a piece of lath or molding. Be careful to keep a good grip on the rag so you can easily remove it.

- If one of these techniques seems to work, run hot water for several minutes to move the dislodged gunk through your pipes and out to the main sewer.

Costs for this work will vary, depending on the company, market and details and scope of the job. Prices ranging from $150 to $220 for simple line-snaking, or as much as $400 if they need to use a cable machine with a blade.

If a plumber or drain cleaner tells you the problem is with your home's main line to the sewer, and that you'll need to replace or reline it at a cost of several thousand dollars, take the time to get a second opinion.

Also, make sure that any plumber you hire is appropriately licensed, insured and bonded, and has positive consumer reviews on a trusted site.

Experts say slow drains are inevitable, but you can reduce their occurrence by following a few steps:

- Don't let hair go down the drain. Wipe it up with tissue paper and toss it in the trash. If you lean over the sink while grooming, cover or close the drain so nothing drops down. Use hair covers for shower drains.

- If your home has old piping, allow hot water to run occasionally, to help move items through.

- Consider using bacteria-enzyme products on a monthly basis to help keep drains clear.

Hopefully, it won't be long until you can declare that "all's clear" in your bathroom.