What to Do When a Garbage Disposal Throws Water Back?

Although you use a powerful or high quality garbage disposal, at some point in time your drain pipe is going to back up. Sometimes this involves water shooting back up from the garbage disposal sink, other times it just means that the drain for the secondary sink backs up and refuses to drain. Regardless of the reason, you need to clear whatever is preventing your kitchen sink from draining. Here are some useful tips for determining the cause of your garbage disposal backup problem, as well as several ways to to prevent it from recurring in the future.

Causes for Garbage Disposal Blockages and Drain Backups

Garbage disposal drains and sink drains get blocked for any number of reasons, but here are the most common to watch out for:

Waste Overload

Don’t throw all of your food waste down the garbage disposal. Vegetable peelings such as potato peelings and carrot peelings should be added to the disposal a small amount at a time with cold water running to ensure that they do not overload the drains capacity and form a blockage. The same is true for any waste cuttings from food prep and any soft food waste left on plates and in pots, pans, and other dishes. Check out Garbage Disposal Do’s and Don’ts.

Onion Skins/Dry Vegetable Peelings

NEVER put dry or toughened onion skins in your garbage disposal, as they are almost impossible for your disposals impellers to grind into small enough particles that wash down the drain. Large sections of onion skin can become trapped in your drain pipe, and in turn they will trap any other food debris that would normally drain easily. Blockage from onion skins are also very difficult to clear without disassembling your disposal and sink drain pipe, so make sure you avoid letting them go down the drain at all costs. Learn more about things you can and can’t put in a garbage disposal.

Fat and Grease

Fat and grease tend to congeal inside of drainage pipes when you pour them down the garbage disposal or drain, and when they build up to a significant level they can easily obstruct the flow of water completely. Allow fat and grease from cooking to cool and congeal, then scrape it into your regular kitchen trash instead of pouring it down the drain. The only way to clear a grease blockage is to use harsh caustic chemicals that may or may not clear the blockage and buildup effectively. An ounce of prevention is definitely worth a pound of cure in this case.

What to Do When Your Drain Backs Up

Most blockages can easily be cleared using the following basic method. Use the following step-by-step procedures in order to attempt to clear the blockage yourself before resorting to more drastic measures such as disassembling the drain or using harsh, highly toxic drain cleaners:

1. Fill the sink with no disposal in the drain with 3-4 Inches of water

If it is backed up and full of water, scoop enough water out that there are only 3-4 inches of water in the second sink.

2. Plug your garbage disposal drain

This is essential for clearing blockages properly.

3. Place a sink plunger (toilet plungers will not work) over the center of your second sink drain

Make sure the plunger you are using has a flat bottom and not a neck for fitting toilet bowl drains.

4. Carefully pump the plunger quickly 5-6 times

Be sure that you the plunger is in fact creating suction between itself and the sink drain. If it’s not, re-center the plunger and try again.

5. Remove the plunger and unstop the garbage disposal drain

Run water down the garbage disposal drain to see if it is now draining properly.

6. If water continues to back up in the garbage disposal, plug the secondary sink and repeat Steps 1-5

If plunging the drain is not effective even after plunging both sink drains, it is possible that the clog in the drain is further down the drain pipe. Should plunging prove ineffective, you will need to drop the trap (u-bend pipes under the sink) and clean the drain pipes manually..

Dropping and Cleaning The Trap

Follow these steps to remove and clear your drainpipes underneath your kitchen sink.

1. Place an empty bucket under your trap to catch wastewater
2. Loosen and remove the threaded plug under your u-shaped sink trap with pliers or an adjustable wrench.
3. Loosen and remove the “elbow” pipe that connects the drain and garbage disposal. Check for clogs or buildup, and hose it out thoroughly to clear any debris.
4. Remove the “tailpiece” or straight pipe descending from the sink drain itself and check for clogs and debris
5. If the clog has been removed, reassemble the trap, plug, tailpiece, and elbow, and tighten them back in place with an adjustable wrench.

Related: How To Unclog Your Garbage Disposal

Snaking Your Drain

Still can’t find the clog even after dropping the trap?  You will need a plumber’s snake to clear the drainpipe that runs under your sink to the outbound drain pipe. Run the snake into the pipe and keep cranking the handle in a clockwise direction until you feel resistance. Keep cranking away until you feel the clog in the drain pipe push through. Crank the handle on the snake counter-clockwise to extract/remove the blockage. Dump any attached debris into the waste water bucket. Repeat as needed until water drains freely down the drain pipe.

Final Thoughts

While it may take some doing to loosen or clear the clog in your disposal or sink drain, the good news is that dropping the trap and snaking the drain are really procedures of last resort. Give the plunger method a try next time your garbage disposal drain or second sink drain is backed up, and hopefully the more drastic measures will not be necessary. Above all, be smart about what you put down the garbage disposal, and you will find that you are clearing clogged drains far less often. Choose the right size of garbage disposal is also important. Selecting one that is large enough for your household can help prevent overflow and clog.