ShelfYears

Does drain cleaner expire?

The caustic that does the work does not — SC Johnson's safety sheet says "no decomposition if stored normally" — but Drano's second active is the same bleach that fades in a bleach jug, so an old bottle works slower.

Updated

Drain cleaner
Sealed
Doesn't meaningfully expire sealed
Opened
Doesn't meaningfully expire
CAUSTIC STABLE, BLEACH FADES
Degraded performance

Sealed: Doesn't meaningfully expire sealed Tier 2

SC Johnson prints no expiration date on Drano, and its safety data sheet for Drano Max Gel records the stability plainly: "No decomposition if stored normally." The sodium hydroxide doing most of the work is a mineral caustic that does not age in a closed bottle. The qualifier is the other active: SC Johnson's ingredient page lists sodium hypochlorite as "a bleach that helps to break down drain clogs," and hypochlorite fades on roughly the one-year clock Clorox publishes for its own bottles.

After opening: Doesn't meaningfully expire Tier 2

There is no separate opened figure and no obvious need for one. The bottle is capped between uses and the sheet asks only that you "keep container closed when not in use." A part-used bottle standing for years is in the same position as a sealed one — full-strength caustic, weaker bleach.

How to tell it's gone off

  • The gel has separated, or gone watery where it was thick.
  • The bottle has swelled, or the cap is unusually hard to break loose.
  • Little or no chlorine smell at the neck, where a fresh bottle is unmistakable.
  • It has spent years somewhere hot — "direct sources of heat" is the sheet's one condition to avoid.

If you use it anyway

Degraded performance

An old bottle of drain cleaner is slower, not weaker where it counts and not more dangerous. The caustic that dissolves the clog does not age; the bleach component that helps break it down does, so a long-forgotten bottle takes longer and may need a second go at the same clog. Nothing about age makes it harsher on the pipes than it was on the day it was filled.

Why it goes off — CAUSTIC STABLE, BLEACH FADES

Two actives, two different clocks. Sodium hydroxide is a stable mineral caustic; the safety sheet records "no decomposition if stored normally." Sodium hypochlorite is the same unstable bleach that decays into salt and water in a laundry jug, and Clorox puts that at about a year before the breakdown accelerates. A years-old bottle is therefore still fully caustic and only partly bleach.

Every page here commits to one of four states — Harmless · Degraded performance · Equipment damage · Safety issue. How the verdicts work.

How to store it

The safety sheet asks for two things and no more: "Keep container closed when not in use" and "Store locked up," away from "direct sources of heat." Its reactivity section is a single sentence, and it is a warning rather than a storage tip — "do not mix with bleach or any other household cleaners."

Never combine drain cleaner with bleach or any other household cleaner.

Sources