The short answer
When a kitchen sink backs up in a Northern Virginia house, where the water comes up tells you where the clog is. Water rising in the other bowl of a double sink, gray water coming up through the disposal, and sink water running into the dishwasher all mean the same thing: the kitchen drain is blocked past the point where the two bowls, the disposal and the dishwasher hose join. It’s almost always grease and ground food, packed into the trap or the line inside the wall. It’s one clog, in one place, and it gets a little tighter every time someone cooks.
If other drains are backing up too, especially a basement floor drain or the lowest toilet in the house, it isn’t the kitchen. It’s the main sewer line, and that’s a different job (sewer backup in the basement).
Where it comes up, and what that means
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| What you see | Where the clog is | How soon |
|---|---|---|
| Water rises in one bowl when you drain the other | Past the tee where the two bowls join: the trap, or the pipe into the wall | This week. |
| Only the disposal side is slow, the other side drains fine | In the disposal or the pipe off its side, before the two bowls meet | Run the disposal first. Dead? Try the reset button. |
| Gray water comes up through the disposal when the dishwasher runs | The kitchen line past the disposal | Soon. It only gets tighter. |
| Sink water runs into the dishwasher | The kitchen line, plus a drain hose with no high loop or air gap (dishwasher not draining) | Soon. Dirty water is getting into a clean machine. |
| The kitchen sink gurgles or rises when the washing machine drains | A line the kitchen and laundry share downstairs, or the main | This week. |
| The kitchen sink and a basement drain back up together | The main sewer line | Today. Stop running water. |
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Why kitchen drains clog the way they do
Bathroom drains clog with hair, close to the stopper. Kitchen drains clog with grease, and grease does its damage farther down. It goes down warm and liquid, cools, and coats the inside of the pipe, and every grain of rice, coffee ground and bit of ground food sticks to it. A disposal doesn’t make food disappear. It makes it small enough to stick. That’s why a kitchen sink that’s been slow for months stops cold after a holiday meal (holiday kitchen drain clogs).
In older houses there’s one more thing. The kitchen line inside the wall is often galvanized steel or cast iron, rough on the inside and narrowed by decades of buildup, so a clog has more to hold on to. You can see a real one coming out in photos of a clogged kitchen sink.
What to try first
- Stop running water into it, and don’t start the dishwasher.
- If the disposal side is the full one, run the disposal with cold water for a few seconds. A disposal full of ground food blocks both bowls.
- Plunge it the right way. Use a cup plunger, the flat-bottomed kind, not the flanged one for the toilet. On a double sink, plug the other drain with its stopper or a wet rag held down hard, or the push just comes up the other side.
- Pull the trap, if you’re handy. Put a bucket under it, loosen the two slip nuts by hand, and clean it out. A packed trap is the easy version (what a P-trap is).
- A hand snake through the trap arm reaches the next few feet into the wall (how to use a drain snake).
What not to do: don’t pour drain cleaner into a sink full of standing water. It won’t get through grease deep in the line, it sits in the bowl, and whoever opens the trap next is working in it (is Drano bad for pipes). Baking soda and vinegar is harmless but won’t clear a backed-up sink (what it does). And don’t keep running the disposal to push it through. The disposal isn’t what’s blocked.
Keeping it from coming back
- Cooking grease goes in a can or a jar, cooled, then the trash. Not down the sink, not even with hot water and soap behind it (what never goes down a drain).
- Wipe greasy pans with a paper towel before they go in the sink or the dishwasher.
- Scrape plates into the trash, not the disposal. Rice, pasta, coffee grounds and eggshells are the usual kitchen clog.
- Run cold water with the disposal, and for 15 seconds after.
- If the kitchen line has backed up twice in a year, a snake only pokes a hole through the buildup. Hydro jetting cleans the pipe wall back to the metal.
What it costs
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| The job | What it is | What it runs |
|---|---|---|
| Cleared at the trap | Grease or food packed in the P-trap under the sink | $99 |
| Kitchen line cleared | A clog past the trap, in the line inside the wall, augered out | $200 to $800 |
| Main line cleared | Several drains backing up at once, cleared with a machine | $550 to $1,650 |
| Disposal replaced | The disposal itself has failed | $550 to $900 |
When to call
Call when plunging doesn’t move it, when it backs up into the dishwasher, when it keeps coming back, or right away if a basement drain is coming up too. SwiftPro’s $99 drain clearing covers the kitchen sink up to the P-trap. Deeper drain or main sewer-line work is a separate service, and we’ll give you that price before we start. There’s $50 off any plumbing repair over $400, and the whole-house plumbing inspection is included with any repair, a $149 value (every current deal).
Book it
Book the $99 drain clearing. Call (703) 997-9757, or book online from goswiftpro.com/cookiesoffer and a box of warm cookies comes with the visit. Our plumbers work in Alexandria, Springfield, Annandale, Arlington and across Northern Virginia, 24 hours a day. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
Why is my kitchen sink backing up on both sides?
The clog is past the tee where the two bowls join, in the trap or the line inside the wall. Plunge with the other side plugged. If it comes back, the line in the wall needs clearing.
Why is my dishwasher draining into my sink?
The dishwasher pumps into the disposal or the sink’s drain. When the kitchen line past it is blocked, the water has nowhere to go but up into the sink. Clear the kitchen drain and it stops.
Why is water coming up through my garbage disposal?
The disposal drains into the same pipe as the sink. When that pipe is blocked, water from the dishwasher or the other bowl comes up through the disposal. The disposal itself is usually fine.
Can I use drain cleaner on a kitchen sink that’s backing up?
Don’t. It won’t get through grease deep in the line, it sits in the standing water, and it makes the job harder and riskier for whoever opens the drain.
How much does it cost to unclog a kitchen sink?
In Northern Virginia, SwiftPro clears a kitchen sink up to the P-trap for $99. A clog deeper in the kitchen line runs $200 to $800.
