Introduction: Unclog Bathroom Sink Without Chemicals

About: I am a DIY person on small scale... fixing things, painting, creating simple solutions... I've been offline for a while, regrouping in my career, going into social work and trauma healing. I teach NVC so will …

My sink has been draining slowly, and finally, people are coming over and we need to clean. It's all backed up, yuck.

The steps of this instructable show you how to remove biological mysteries from your sink's drainage without using caustic chemicals that cost money, are bad to breathe, less fun and whose success as an unclogging strategy has a lot of uncertainty.

My bathroom sink is simple enough that the pipes and pop-up assembly do not require any special tools to take apart and put together. The only tool I employed besides my hands was an old tooth brush.

This job takes me about 15 minutes; less time than it takes to go to the store and back to buy those old chemicals.

I read that you can keep pipes from bioaccumulating by putting down 1/2 cup baking soda, then 2 cups very hot white vinegar, wait 1 minute, bubble bubble, then follow with 2 cups very hot water.

Step 1: Prepare for Cascading Water and Biofilms

Take all your cleaners, electronics, Make magazines and paper supplies out from under the sink. 

Install nice large plastic tub. I prefer a tub to a bucket so I can get my hands in there and so I can see the wonderful microbial masses that come sliding out.

Step 2: Detach and Clean U-bend Pipe

Unscrew ends of the u-pipe, remove, empty water and clean out hair and bio-critters.

Step 3: Remove and Clean Tail Piece

Slide tailpiece pipe from sink drain pipe. Yours may need to be unscrewed.

See culprit biofilm on inside of the pipe.

Push microbial communities out, screaming and crying, with your toothbrush.

Step 4: Clean Sink Drain Pipe

Get tooth brush up into the sink drain pipe.

The horrors that come out!  Kind of thrilling, isn't it?

Thank goodness there are no instructables for a kefir-kombucha-pipebiomass hybrid fermented health drink.

Step 5: The Stopper

The stopper won't come up because it is still hooked into the pop-up assembly.  It is connected underneath to a horizontal rod that links it the lift rod (the pull-up knob you use when you want to engage the stopper and fill your sink with water).

Step 6: Decouple Stopper and Lift Rod

Unscrew the pivot nut that holds the horizontal (pivot) arm onto the popup assembly.

In my sink, the horizontal pivot arm can come out of that hole, is not attached. I just disengage the connection and rest the end in the hole for a bit.  The pivot nut stays on the horizontal arm so you don't lose it.

I found tips and vocabulary from the Natural Handyman website on bathroom sinks.

Step 7: Clean Stopper and Drain

Now you can pull the stopper our and find all those wonders to clean!

Then push your toothbrush down into the drain and force the refugee masses down into your tub.

Step 8: Reattach Popup Assembly

After scrubbing your stopper and drain hole clean, place stopper back into drain hole with flat area and connection hole toward the back of the sink, so that side is closer to the lift rod.

Hold up the stopper by a cm or so with one hand, while reaching under the sink with the other hand adjusting the horizontal rod to get that plastic shaft into the hole at the bottom of the stopper so they are connected.

Step 9: Test Connection!

Test to see if the lift rod and stopper are attached. Move end of the horizontal rod by end of the lift rod up and down. The two should move in opposite directions together, like pop goes the weasel.

Step 10: Reconnect Things

Natural handyman recommends to slather some plumbers grease on the ball. I don't.

Screw on the pivot nut locking the horizontal pivot arm in place. Not too tightly, and not too loosely. If the lift rod doesn't stay up, you might need to tighten the pivot nut a bit. 

Slide the tailpipe back onto the drain pipe (mine fits without tightening).

Reconnect the u-pipe by tightening each end a little in turn.

Step 11: Test, Compost, Maintain

Run the water; see the clean water go down the clean uninhabited pipes!

Look below, are there leaks? Tighten nuts as needed. 

What to do with this big biological party in the tub?

Compost it!

Every 3-4 weeks you can put 1/2 cup baking soda followed by 2 cups hot vinegar, wait 1 minute, than add 2 cups super hot water to keep pipes colony-free.

Hydrogen ions from the vinegar react with the bicarbonate ions from the baking soda to form carbonic acid. The acid acts on the biofilm while decomposing into water and carbon dioxide!  So simple and clean!  See this instructable by

I don't bother with that, I just clean out the pipes about 3 times a year.