9 Reasons Sinks Drain Slow Even When Not Clogged


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While it is easy to always think a clog is a reason for your slow-moving drainage, there are other reasons that can be the culprit.

If you know that there isn’t a clog in your system, here are seven other reasons that your bathroom or kitchen sink may be draining slowly.

Tree Roots

One of the reasons why you may be experiences a non-clog related drain slowing is from tree roots. When tree roots grow into the sewer line, you’re going to have issues throughout the entire system. To fix this issue, a plumber will need to remove the roots and replace all the damaged area of sewer pipe.

While this is a costly procedure, there is really nothing that can be prevented. However, tree roots tend to grow slow so just because you have a home around trees does not mean that you will automatically get this problem.

Septic System Issues

Just like tree roots that grow into your pipes can cause drainage problems, so can having issues with your septic tank. Septic tank sludge can form throughout the lines and tank and when this happens there is a chance that it will block up the main line.

When the main line is blocked, there will be slow-moving drains throughout your entire house. This is again a job for a plumber once it happens, as they are able to remove the sludge from the system.

For prevention, finding a good septic tank treatment(amazon) will help keep your system sludge-free and clean.

Lodged Items

Ever drop a piece of jewelry down your sink or find half of a toy dinosaur sticking up from the drain? Items can find their way into the opening of the pipes and when this happens it can lead to water draining slowly. One of the easiest ways to try to dislodge this is by getting a metal clothing hanger and straightening it out.

By looping it at the end you may be able to pull out whatever is causing the slow drain release. If this doesn’t work, you’ll need a plumber to remove that section of the pipe and clear the blockage.

Soap

I know you’re saying, “Soap?” but soap can have scum buildup in a pipe just as it can on your shower. As this buildup happens, it can become like scale and hinder the flow of your water through the pipe. This is especially true if you have mineral-heavy water. The only prevention to this is by trying to lower the mineral content of your water by using water softeners.

Food Particles

Just like other lodged items, even food can find its way wedged in a pipe. While the natural breakdown of the food can lead it to self-dislodge, there will also be smells associated with that.

Seatery 2PCS Kitchen Sink Strainers, Sink Drain Filter, Sink Basket Strainer, 4.5 Inch Stainless Steel Sink Drain Strainer, Food Scraps Catcher for Kitchen

Food-catching drain covers can help with how often stray food will fall into the trap and there are special drain deodorizing tablets that are made to help with the smell. If there is a lot of food, this can lead to an actual clog in the pipe system.

Aged Plumbing Fixtures

While modern and new fixtures will typically not have issues, old plumbing has a much harder time.  A slow draining sink can be a symptom of aged plumbing. While it could be problems with the fixtures themselves, it could also be an issue of the pipe or fixture not being able to handle the new household load.

Drains, sink fixtures(amazon), and pipes are all part of the entire flow system to your kitchen or bath, so by keeping it all up-to-date, you’re keeping everything functioning well.

Having a good maintenance plan where you do a yearly overview is a habit that will help not only keep your drains flowing fine but also help you see problems before they turn into serious issues.

P-Trap Clogs

Clogs in the P-Trap are different than standard pipe clogs in that it is lodged directly under your sink in a small section of pipe that is bent. This trap layout makes it difficult to see a clog from above and also makes it harder to remove the standard ways.

P-Traps(amazon) can be removed and cleaned or replaced if you’re handy, or call a plumber if you would rather not get your hands dirty.

 To clean them yourself, place a bucket under the P-Trap. Use pliers to unscrew the two coupling nuts on each side of the trap and when loosened, pull the trap down.

The bucket will be there to catch water and waste. A bottle brush can go inside the trap to clean it out. Once cleaned, reattach and tighten down the coupling nuts. If you cannot clean it and it is clogged tight, you can buy replacements and hook it into the system just like the one you just removed.

Vent Pipes

These type of pipes will let air through to create a vacuum, allowing equalization of pressure and removal of odor causing gases. If the pressure is not in balance, there can be slow moving drains.

You’ll need to check to see where your vent pipes are located and check for issues. Winter sees the highest number of vent pipe issues as the snow, ice, and leaves can build up. When these blockages are removed, the issues will go away.

Basic Deterioration

While basic deterioration can be just like aged plumbing and be caused simply by age, it can also be caused by corrosion from chemicals. Being mindful of the types of cleaners you use around the kitchen and bath could help extend the life of your pipes. Chemical cleaners allow for quicker corrosion of pipes than non-chemical cleaners(amazon).

Rust is another prong in the basic deterioration reason for your slow moving drains. If your pipes are rusty, old, or deteriorated, there is nothing to do but to call a licensed plumber. While you can try to slow down the speed of deterioration by using less chemicals throughout the house that will go down the drain, eventually all houses will run into this issue.


These seven reasons are not the only issues that can cause a slow draining system, but they are the most common ones after a clog. While annoying, slow draining sinks can be a sign of a much bigger, and costly, issue.

Preventing issues in your drain system can include regular septic treatments to reduce sludge, using hot water to clear out grease buildup, and placing drain covers to catch any items that may try to snake down the pipes that shouldn’t be there.

No matter the issue, with a little bit of handyman ability or calling a licensed plumber, your issues should be fixed and your drains flowing like new.

Related Artice: Sewer Smell When Running Bathroom Fan

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