Sulfuric Acid Drain Cleaner

I was watching a home chemist video on YouTube and they said if you couldn’t get lab-grade sulfuric acid from a chemical supplier, you could buy it at the hardware store as a drain cleaner. Sure enough, you can actually buy it at the local Wal-Mart. According to the reviews, it’s either the best drain cleaner EVAH or it totally wrecks your sink or toilet, requiring hundreds of dollars in repairs.

So, what’s the Straight Dope here? I find it hard to believe it’s actually safe to pour sulfuric acid into your bathroom sink. :eek: Are there places that have laws against this?

unbeknownst to me my house settled and the upstairs drain line no longer had a slope. The drain cleaner ate a 2" by 8" hole through the cast iron pipe. Gravity ensued and It made for a bad day.

I only messed with sulphuric once with limited results. But hydrochloric/muriatic acid is great stuff for slow drains. Eats away all the scum, salts, rust chunks and gets things moving. Would not advise it for a total clog though, because if it doesn’t work… Also I usually dump some soda or lye in after enough time has passed to neutralize things. So, in short, acid is useful stuff if used right.

chemicals are a poor choice for drain cleaning.

it is a serious hazard to skin and eyes. if it doesn’t work you have a dangerous chemical that will cause harm to your plumbng and house if not neutralized.

Should add to my previous post - run lots and lots of water after the acid. Especially before adding any class of base.

Our house’s previous owner left behind a bottle of sulfuric-acid drain cleaner. No way in heck would I trust myself to work with it, and my house is so old that there could be old, fragile pipes somewhere along the drain line. This means that I have a bottle of an absurdly dangerous substance lurking in my workroom, and I keep forgetting about it when the city has a toxic liquid day at the dump. It’s kind of a cursed potion for me at this point.

Surely it depends on the pipe material? A copper pipe will be fine, while a cast iron pipe will react rather readily with it.

Sulfuric acid probably isn’t any different from a reactivity perspective than muriatic (hydrochloric acid), but it can be made more concentrated.

Maybe it’s the chemist in me, but working with strong chemical cleaners is quite safe, provided that you know what your plumbing is made out of, and take appropriate safety precautions. The biggest concern is protecting the eyes. A little acid or lye on the skin can be washed off and will only leave a superficial burn, but getting some in the eye, especially a strong base, could mean permanent damage.

Could not agree more. I never use chemicals on normal drains. The only time I remember using a chemical drain cleaner was where the drain was in the slab. X Ray film developer over drain so I could not get a snake in it.

My 1st experience with chemical drain cleaners was sometime in 1968 as a Third Class Midshipman at the maritime academy. Someone had tried chemical drain cleaner is a drinking fountain drain. And when that did not work the pipes had to be taken apart. The midshipman taking the lines apart got some of the cleaner in his face. He dropped the lines and what was in the lines were dumped all over the engine room. He went to sick bay and I got the pleasure of cleaning the stuff up. Remember if you pour dangerous stuff down a drain you may get stuck having to clean it up or calling and paying someone to clean it up.

If you pour ANY active chemical in a drain (Draino is lye, or was), your plumber is NOT going to like you.
For instance - a clogged or blocked vent will cause a slow drain. If the problem is the vent, you can run anything you want down the drain - it will not fix the problem, and may produce a MUCH larger one.

Biggest point - should you end up calling a plumber, TELL HIM/HER WHAT IS IN THE PIPE. Plumbers often get a face full of the drain contents - they need to know to how to approach.

I heard of one poor soul who was working in an MD’s office and had his lips slightly apart when opening the pipe - he picked up a disease.

Cruising message boards of various professions can be entertaining and informative.

I am just wondering what is likely to happen if I dump some Lye in the drain, after the H2SO4.

Would or could there be any reactions between acidic drain openers and PVC pipes? In other words, would acid destroy the PVC the way an earlier post says it would destroy/erode iron pipes?

Don’t know if my revious reply made it… Would acid type drain openers have a negative impact on PVC pipes?

Why can’t it be both, like the late Earl Warren?


One-Shot-Instant-Drain-Cleaner contains 91% Sulphuric Acid

There is a device called a ‘drain king’ that I have used on many clogged pipes in old houses over the years. It is basically a water powered snake that uses water pressure and vibrations to loosen and force out clogs. Sometimes you have to use it at several clean-outs to get the clog debris all the way out to the sewer. It is not going to clear out roots but it works great on slow pipes, grease and hair clogs. It is easy to use, safe and of minimal mess. It works so much better than chemical drain openers there is no comparison. It does have to be used according to instructions or you could end up very wet or with a clogged vent.

That being said , the pros use a snake. Plumbers don’t bother chemical openers or a ‘drain king’ (as far as I know), they use a snake, or call the guy that specializes in snaking. I am a sissy and grossed out by evil pipe sludge so I use the drain king instead of a snake. There is a reason pros use the tools they do though.

There’s nothing in the article about the drain pipe being PVC.

you would have a violent chemical reaction, it might splash both caustic chemicals around which is dangerous.

mixing strong chemicals together without knowing what you are doing is hazardous and potentially deadly…

neutralization of chemicals has to be done properly to not create additional problems.

How do strong acid cleaners affect septic systems?

Sulfuric acid appears to be safe with PVC pipe:

You need to make sure that your pipes are really pvc all the way: sulfuric acid will eat into any steel pretty quickly.

If the acid doesn’t work, and then you run water down there to check if it’s working, it gets very, very hot, and can actually melt your PVC. I . . . know someone . . . who did this once.

ETA: Upon research, I see that this was probably sodium hydroxide, not sulfuric acid.