Slow flowing or flushing toilet? Here are some things to try if the weak flush is caused by an obstruction in the bowl's rim where water is discharged. Toilets with this problem typically quickly accumulate unwanted deposits because the flush leaves portions of the bowl unwashed. The procedures discussed will not fix the toilet if dumping a bucket of water in the bowl causes water to "back-up" instead of forcing a normal flush. The use of muriatic acid in such circumstances would be both ineffective and extremely dangerous.

Show Ads

[edit] Steps

Figure out where the problem is. Fill a bucket or plastic trash can with a gallon or two of water and pour it quickly into the bowl. If it flushes slowly, you probably have a clog and the procedures on this page will not solve your problem. Instead use a plunger, plumber's snake, or closet augur to clear any obstructions. See the related article about unclogging a toilet. If however the toilet now flushes quickly, the problem is with water delivery. Read on:
Use a bent coat hanger and mirror to remove deposits in the holes.

For slow water delivery and/or if water does not evenly "wash" the bowl, the usual method is to use a toilet brush and a pumice stone to clean the bowl paying particular attention to the area up under the rim. There are small holes there that dispense water into the bowl and these plus the surrounding area must be cleaned of mineral deposits. If necessary, use a pick such as the bent end of a wire coat hanger to clear the holes. Try not to scratch the porcelain however as this encourages deposits to quickly form again. A small mirror will help you see what you are doing under the rim. Brush the bowl and rim again and check if the above approaches have worked. If they have, you're done. Otherwise, read further:
If your toilet is extremely affected by mineral deposits and/or you're hoping to skip the manual cleaning steps above there is perhaps another way using the magic of basic high-school chemistry. However, there are serious safety issues to consider before utilizing this approach and it should really only be considered as a last resort (instead of replacing the toilet) by experienced, dedicated do-it-yourselfers. Study the following steps, tips and warnings and decide if you are capable of safely using muriatic acid. Do not buy muriatic acid until you are ready to use it and read, understand, and be prepared to follow all the bottle's directions and cautions before you even carry it to the checkout. This stuff is extremely strong! Keep it well away from children and pets. Muriatic acid is not an option if you are on a septic system as it would kill the bacteria that makes the system work so you must use only "septic safe" methods and cleaners.
Turn off the water to toilet and flush. Use a plunger and/or a sponge and remove the water left in bowl so that the acid will clean the bowl to the bottom (including the critical jet-hole).
Use a clear piece of poly-film (or a clear trash bag) and tape and cover the top portion of the bowl while retaining a view of the bowl's internal rim. The tighter the seal the better. Just cover the bowl portion, do not include the seat.
Maximize ventilation by placing a running fan in the bathroom window to exhaust air. Also open all other windows in the home. If you have a bathroom exhaust fan, turn that on too.
Take off the tank cover and insert a plastic funnel into the overflow tube. See the "things you need" section about the correct size of the funnel. If there is a tube going to the overflow tube, carefully take it off first.
Wear gloves & eye protection and have an equally protected assistant firmly hold the funnel in the overflow tube so it cannot fall out. Carefully pour acid through the funnel fast enough that it begins to flow out of the holes in the toilet bowl rim but not so fast that the funnel overflows or falls out as this would splash acid & be extremely dangerous. You will only need about 0.5 to 1 gallon of acid. After pouring, cover the overflow tube with the sandwich bag and rubber band, then leave the bathroom and close the door behind you. Lock the door if children are in the house and make absolutely certain they stay away.
After 1 hour, remove the sandwich bag and replace the fill tube to the overflow tube. (If you've chosen a weaker acid this needs to be prolonged to at least overnight.) Turn on the water and flush a few times. Extra flushes are advisable in older homes with iron waste pipes as prolonged contact with concentrated acid will damage them. Check the rim holes for proper operation. Repeat the procedure if necessary or if there is leftover muriatic acid because it is not safe to store this stuff around the house.

[edit] Tips

Some toilets just flush slowly because of their construction but if your toilet flushes more slowly over time (without "backing-up"), it is likely due to mineral deposits in the holes under the rim. If clearing the holes does not work, you may want to look into replacing the entire toilet. In fact there are many arguments for replacing the toilet instead of using dangerous chemicals. Modern toilets have drastically reduced their water requirements and better ones have computer-tested designs that work almost as well if not better than the older ones that used many more gallons of water.*
It is also possible that the jet hole is partially clogged with something that muriatic acid will not remove. The jet hole is the small hole near the bottom of the bowl. Its purpose is to establish the siphon that provides the suction to empty the bowl. In a complete flush, just as the bowl fully empties you hear a "glurp!" which is the sound of the siphon sucking an air bubble and breaking because there is no more water to suck out. The jet hole is below the water line and checking it is, shall we say, unaesthetic! But it's very easy to do. First attack the bowl with a plunger to force out water to allow easier access to the jet hole. Now insert a finger into the jet hole and feel around for an obstruction. Use caution because there could be sharp edges. In my case, I found a rubber washer loosely sitting in there. Flushing the toilet would push the washer up against the jet hole partially blocking it. I used a pair of miniature long nose pliers to fish out the washer (which probably fell into the tank during previous repair). It was surprisingly easy and did much to solve my problem.
Muriatic acid will attack hard-water deposits in your toilet bowl better than any other product sold to consumers. If you need a septic-safe acid or are uncomfortable using a powerful but dangerous acid, you can try one of the numerous lime, calcium, or hard-water deposit removers such as CLR or even white vinegar (acetic acid). These are far safer but much less effective on the stubborn, somewhat inaccessible deposits inside a toilet rim. These products will also need a longer "soak" period (perhaps overnight) and followup with the mechanical action of a pick such as a coat-hanger. Several cleaning cycles may be necessary. Although muriatic acid is very dangerous, it is actually one of the safest of the "strong" acids found in the chemistry lab hence its presence on retail store shelves.

[edit] Warnings

Try the Muriatic acid treatment at your own risk! Muriatic acid is extremely strong and it should therefore be considered as a last resort prior to replacing the toilet by experienced, dedicated do-it-yourselfers. If you have any doubt about your ability to handle this strong acid, consider trying the other approaches and safer chemicals or replace the toilet!
Muriatic acid could destroy the tank flapper, the tank to bowl rubber seal, and any metal parts on older toilets such as the overflow tube. If you don't have the skills to replace these parts yourself, consider using one of the weaker acids or buy a new toilet.
Do not attempt the Muriatic acid procedure unless the area can be well-ventilated. Maximize ventilation by placing a running fan in the bathroom window to exhaust air. Also open all other windows in the home.
Wear rubber gloves and safety goggles for eye protection and ideally an OSHA approved mask designed to prevent the inhalation of acid fumes.
Read all the precautions on the acid bottle and be sure everybody in the area becomes familiar with the procedures it describes for handling accidents. Be very careful when using acid. Keep children and pets away from the area.
Never mix household chemicals as this could cause blindness by creating violent reactions that spray chemicals unexpectedly and uncontrollably, release large quantities of toxic if not lethal gasses, and release heat that could crack the toilet. If you have toilet-cleaning pellets in your toilet tank, use rubber gloves to remove them and place in a clean sealed plastic container, then flush to clear before using other chemicals. If you clean the toilet with toilet bowl chemicals, flush numerous times before adding any other chemical to the toilet. If you have used drain cleaners, flush them away numerous times and allow plenty of time before adding Muriatic acid or any other toilet chemicals.
Do not use the Muriatic acid procedure on a toilet if it "backs-up" instead of emptying normally when flushed or tested with a bucket of water.
Do not store left-over muriatic acid. Either repeat the procedure or slowly and carefully pour the leftover in the bowl and flush it thoroughly away. This stuff is so strong that it often eats through the plastic container if it is stored for a prolonged period and it is simply not safe to have it laying around.
Never use muriatic acid to clean hard-water deposits on any other surface or in any other way unless you really understand what you are doing.
Avoid getting debris in the tank. If it goes down the discharge pipe, there may be no getting it out of there.
Muriatic acid cannot be recommended for septic systems as concentrated acid will kill the bacteria that makes the system work.
Rinse the funnel well and do not reuse it for food.

[edit] Things You'll Need

Bucket
Wire coat hanger
Mirror
Bowl brush
Muriatic acid, 1 Gallon (Available at hardware stores, pool supplies, & Target/Walmart seasonally.)
Tape
Trash Bag
Sandwich bag
Funnel (This must be plastic, as large as possible, and should fit snugly into the toilet tank overflow tube.)
Rubber gloves (2 sets)
Safety goggles (2 sets) & ideally two OSHA approved masks designed for acid fumes
Rubber band