How to remove hard water stains from a toilet (rings and limescale)

Step by step: how to remove hard water stains from a toilet

Safety first. Acid cleaners and bleach release toxic gas when mixed. If the bowl or tank holds any bleach cleaner or a bleach tablet, flush several times and remove the tablet before you use an acid or vinegar. Wear gloves and eye protection, and ventilate the room.

1. 1

   Identify the stain

   Hard water stains are chalky white, tan, gray or orange rings at the waterline, crusty buildup in the drain hole, and streaks under the rim. They feel rough when you rub them with a gloved finger. Black, fuzzy or slimy spots are mold instead and need a bleach cleaner, on a different day.

2. 2

   Lower the water level

   Turn off the supply valve behind the toilet and flush to empty the bowl. If water remains below the ring, push it down the drain with a plunger or sponge it out. Cleaner on a dry stain works at full strength instead of being diluted.

3. 3

   Apply an acid cleaner to the ring

   Squeeze a lime and rust toilet cleaner around the rim and directly onto the ring, then brush it over the stain. Leave it for the time on the label, often 5 minutes for a regular clean and longer for heavy scale if the label allows.

4. 4

   Or soak the ring with vinegar overnight

   For a gentler method, press paper towels onto the ring and soak them with white vinegar so they stick, or pour 2 to 4 cups of vinegar into the empty bowl. Leave it several hours or overnight with the water off, then scrub. Vinegar works more slowly than a commercial acid cleaner.

5. 5

   Scrub and flush

   Scrub the ring hard with the toilet brush, then turn the water back on and flush. Check the waterline in good light. Light rings usually come off in one round; old, thick ones need a second soak or the pumice step.

6. 6

   Work off old scale with a wet pumice stone

   Soak a toilet pumice stone in water for a minute, then rub the ring gently with the stone and the porcelain both wet. The stone wears down as it grinds the scale away. Test a small spot first, keep it wet at all times, and stop when you reach smooth porcelain.

7. 7

   Clean under the rim jets

   Mineral buildup in the rim holes causes streaks and a weak flush. Apply the acid cleaner under the rim with the bowl drained, wait, then poke each hole gently with a bent wire or small brush. Flush a few times to rinse.

Why bleach doesn’t remove hard water stains

Bleach doesn’t work because mineral scale needs an acid to dissolve it, and bleach is alkaline. Hard water rings are built from calcium and magnesium; the USGS describes water hardness as the amount of dissolved calcium and magnesium in water.

Clorox says rust and hard water stains require acidic cleaners with a pH under 7, that its bleach is alkaline, and that bleach should never be mixed with an acid because hazardous fumes may form. For heavy stains, Clorox suggests turning off the water and flushing so the cleaner goes onto a dry surface.

Which hard water stain remover should you use?

Start with the gentlest option that matches how thick the ring is, and move up only if it doesn’t shift.

CLR’s directions list toilet bowls and porcelain among its uses, but say to mix it with an equal part of warm water, leave it no longer than 2 minutes, rinse promptly, and never mix it with bleach or other cleaners. Bar Keepers Friend is an acidic cleanser and recommends leaving it on a surface no longer than one minute.

How to keep hard water rings from coming back

Brush the bowl weekly with an acid cleaner so minerals never get a chance to build up in layers.

• Flush spare toilets every few days; still water leaves a ring as it evaporates.
• Use an acid cleaner on alternating weeks with your regular cleaner, flushing well in between if the other one contains bleach.
• A whole-house water softener reduces scale on every fixture, not just the toilet.
• For hard water on glass, tile and faucets, see our general guide to removing hard water stains, and our toilet bowl cleaning routine.

Mistakes to avoid

• Using bleach on a mineral ring, which can’t dissolve it.
• Adding vinegar or an acid cleaner to a bowl with bleach cleaner or a bleach tank tablet in it.
• Pouring cleaner into a full bowl, where the water dilutes it before it reaches the ring.
• Rubbing with a dry pumice stone, which scratches the glaze.
• Using steel wool or a wire brush, which leaves gray marks and scratches that stain faster.
• Leaving CLR on longer than its 2-minute limit.