Black Swan 09020 ZAP Drain Pipe Opener, 32 Ounces, Heavy-Duty Formula Clears Clogged Drains & Waste Lines, Thaws Frozen Lines, Disintegrates Organic Matter, Safe for Septic Tanks

Clogs that would not yield to conventional lye-based drain openers were quickly cleared with a satisfying "woosh" as soon as I poured this acid-based product down affected drains. Multiple sinks and a bathtub/shower are usable again! Yes, you have to take precautions with this product (read the label). Yes, there will be a temporary "rotten egg" smell as the acid clears the drain. But this product is absolutely no joke and may save you a plumber visit.

Works great on backup sinks

This stuff works like no other. Our shower drain, 25 years after construction, was full of hair and soap. One or two prescribed doses does the trick. This is after years of the store-bought drain cleaners and online lye-based cleaners just muddled along. Those lye products can loosen the debris, but just enough to slow the drain or, worse, harden into a solid clog.This sulfuric acid breaks through without clogging. (Though instructions and other online advice do caution severely, don't follow other products with this strong acid.) Follow every caution and warning in the instructions and online advice. Google sulfuric acid in drains. There are some disasters out there -- this is the real thing.Buy the heavy black pvc coated, chemical resistant, elbow length gloves, and use good eye protection. If it will eat through what's in your drain, it will eat through your skin and eyes. It sort-of "explodes" up out of the drain when it interacts with all the crud you're trying to get rid of, so stand back. And use a fan and exhaust fan so you don't breathe the toxic fumes.But it works!! Nothing works like this, and I think we tried them all before.If you are competent to handle dangerous sulfuric acid, you'll be pleased with how well this stuff works....ADDING THIS IMPORTANT SAFETY CAUTION ALMOST A YEAR LATER....Just to reinforce the safety cautions I see in the few negative reviews here, and on google regarding sulfuric acid in drains .... If you have used lye-based products and consider using this acid, be absolutely sure you have washed all of the lye out of your drain multiple times before using even a tiny dose of the acid. If there is still lye clogged in there (apparently this happens commonly, based on reviews and other online disaster stories), the acid will explode violently and dangerously up out of your drain with amazing force. You'll be cleaning your walls and ceiling for hours, if it doesn't get in your eyes and send you to the emergency room. The company seems very responsible to warn us in their instructions on the bottle. I'm just saying, please take these cautionary tales seriously.

The drain cleaner works great for tough clogs

i dont ever plAn to go back to weak foamy stuff with cute mascots, if you need to clear a drain, that's what this does... no pussyfooting around.nicely packaged, ive never had a problem with spillsreccomended

If you want to destroy all of the pipes in your home, use this! If you want to spend a couple thousand dollars on a plumber after using this, by all means, USE THIS! This is nothing but pure acid! It literally burns right through metal pipes! No pipes left in the walls or ground or underneath your sink or wherever you use this. Stay away from this! You've been warned. Smh.

Clogged drains go bye-bye!This product does exactly what it's advertised to do but be careful using it. Be careful storing it. Just be safe.We had a slow-draining sink and shower in different areas of the house. Used probably half of the recommended amount and this cleared both back-ups in a matter of minutes.Personally, I ran the water momentarily after pour it down the drains (I found a similar product called Clobber through a plumber and this is virgin sulfuric acid as well and does the same thing).A plumber would probably charge you a couple hundred bucks to fix a back-up; or just buy this!5/5.

This is my first review on a product and this deserves 10 stars! My kitchen sink was very slow draining and knew it was only a matter of time before it was 100% plugged. I had tried several other methods and products and nothing helped. I read the reviews and decided to try. Used 2 cups and poured slowly and waited. I did put a bowl over the drain b/c I could see and smell fumes. I waited 20 min., everything drained, but when I started to use the faucet, it started to fill up again. I then used a plunger for 5 seconds and the clog came loose. I'm so relieved it works!!!