The 10 Best Enzyme Drain Cleaners

For a whole house, septic tank included, Bio-Clean Drain Septic covers the most ground. It's a dry blend of bacteria and enzymes that you stir into water and pour down a sink, tub or toilet, and one can holds about 100 drain doses. The maker gives directions for each kind of drain. Patience is the catch: results take one to three weeks, and it does nothing to mineral scale or anything that isn't organic.

Kitchen sinks that smell of old grease are where Green Gobbler Enzymatic fits best. The liquid pairs enzymes and bacteria with a mild soap, and it skips lye and bleach. Green Gobbler suggests a small weekly pour for a drain and more for a grease trap or septic tank, so a jug lasts. It fixes odors more reliably than it opens a drain that has already stopped, and the maker rules it out for sudden toilet clogs.

Cheap to run month after month, Zep Drain Defense is a powder you shake into a slow kitchen or bathroom drain and rinse down. A tub holds up to 40 treatments, or years of monthly doses for one sink. Zep has made janitorial cleaners for decades, and this one is safe for septic systems and all kinds of pipe. Zep rules out hair clogs, though, so a shower drain matted with hair needs a plastic drain snake first.

For a mild herbal smell at the sink, try Mrs. Meyer's Probiotic, a lemon verbena liquid made mostly from plants. It carries bacteria spores plus enzymes that break down starch and fat. The first dose is half the bottle, left overnight in warm water, and after that a small pour every few weeks keeps pipes clear. That first dose drains the bottle fast, and the maker asks anyone with a weak immune system to check with a doctor first.

Septic owners who want a routine with no measuring can drop one pack of Rid-X Septic Tank Treatment in the toilet each month and flush. The dissolving packs hold enzymes and bacteria meant to break down paper, grease and food waste in the tank, and one box lasts a season. It treats the tank, not the pipes, so it won't help a slow kitchen sink, and no additive replaces having the tank pumped on schedule.

The pipe that runs from the house to the street or the septic tank is the target of Roebic K-97, a liquid of bacteria and enzymes. You pour part of the bottle into a toilet each day for four days in a row, and Roebic suggests repeating the course about twice a year, which keeps the yearly cost low. It works slowly, it won't move tree roots or a broken pipe, and Roebic's own site says little about what's inside.

Drano, the name most people know for clog gels, makes Drano FlowGuard for the opposite job: keeping a clear drain clear. It's a bleach-free liquid with enzymes and probiotics and a citrus scent, poured once a month into a sink or toilet, and it's safe for septic systems and both metal and plastic pipes. Drano is blunt about the limit, though. It will not open a clog, so standing water still calls for a plunger.

Built for commercial kitchens and soda fountain lines, InVade Bio Drain is a thick gel that clings to the pipe wall instead of rushing past it, giving its microbes more time on the slime. Rockwell Labs says a gallon covers about 32 drain doses, and the gel is NSF registered, which matters in food service. It's a common choice for damp drains that breed small flies. It costs more up front, and it works over days, not minutes.

One jug, three chores: AmazonCommercial Enzyme Cleaner is a mint-scented concentrate meant for carpet stains, litter boxes and drains, with nothing caustic or acidic in it. That makes it a sensible buy for a home with pets that wants one bottle under the sink instead of several. It's a general cleaner first, and the seller lists it as no help for a hair-clogged bathroom drain.

Twice a year, the whole bottle of Roebic K-37 gets poured into a toilet and flushed, and then the house goes easy on water for several hours so the bacteria can settle into the septic tank. Each dose costs little. The quart is sized for a modest tank, so bigger tanks need more. Like any additive, it's no substitute for pumping, and the proof that additives help a healthy tank is thin.