Troubleshooting a Vessel Sink that Drains Slowly

Modern bathroom with white vessel sinks

A vessel sink can add more to the beauty of a kitchen or bathroom, but like other plumbing installations, vessel sink drains are subject to the same problems such as slow draining. There are a lot of causes for a slowly draining vessel sink, but you can typically tackle problems yourself. Do not attempt a repair if you are not confident in your ability.

Soldering pipes, replacing valves, and changing faucet seats should be left to skilled persons with proper tools if you are in doubt. If it has just been clogged by something, you can attempt to unclog it by using commercial drain cleaners but always read the instructions carefully to avoid contaminating your drinking water with chemicals. If rusty pipes are the cause, do not apply too much force on them since it can worsen your problem.

Step 1 - Acknowledge Common Draining Problems

plumbing trap below a sink

One of the most common draining problems that you may encounter in a slow draining vessel sink is low water pressure. If opening the sink faucet causes water pressure to drop on your whole plumbing system, there must be a defective plumbing part somewhere or your vessel sink has been installed the wrong way.

You may also find that aside from draining slowly, water is backing up on your sink. You may also observe wet spots on walls and floors of the rooms that border the walls containing your drain pipes. There are instances when the slow draining is accompanied by a bubbling or gurgling sound along the pipes.

Step 2 - Identify the Extent of the Slow Draining Problem

If slow draining is localized to the vessel sink only, then the problem must be on the particular pipe that connects it with the main plumbing line. However, if the slow draining problem can be observed in other fixtures on the house such as other sinks, the bath tub or commode, the problem might be in the main plumbing line which carries all the wastewater from all of the fixtures you have installed in your house.

If the problem is isolated to your vessel sink, you can try following the route that wastewater takes to the main pipe. This might be quite difficult if your sink pipe has been connected with other pipes that are routed through wall cavities before going below the floor line.

Step 3 - Flush Drain Pipes

sink drain with water running

If you have identified clogs to be the cause of a slow draining vessel sink, you can try removing them by plugging the drain first and then filling the sink with hot water. Once it has been filled fully, unplug the sink and let the hot water drain into the clog. If the clog material is made of grease, the hot water will melt it enough to restore normal flow. You can also use drain cleaning chemicals to dissolve clogs.

If the clog cannot be removed by the above method, you can use a plumber’s snake, but be careful with it. See some of our related articles to find help using a snake properly.