What MaP Testing Tells You About a Toilet
MaP — Maximum Performance — is independent third-party testing of how much a toilet actually clears in a single flush. A model's MaP score is the grams of test media it removes completely in one flush, tested at set intervals up to 1,000 g [1][2]. It is the one specification on a toilet box that was measured by somebody other than the manufacturer.
What the test actually does
The test uses a repeatable stand-in for waste: soybean paste formed into 50-gram specimens, normally in a thin latex casing, dropped into the bowl together with four loosely crumpled balls of toilet paper, and flushed with the toilet set to its own rated flush volume [1]. Test masses step through fixed intervals — 350 g, 400 g, 500 g, 600 g, 800 g and 1,000 g — and the score is the largest mass the fixture clears completely, restoring at least a 2-inch trap seal, in at least four of five attempts [1].
It is deliberately unglamorous, and that is the point: the same media, the same dose, the same procedure, done by a laboratory that does not sell toilets [2].
- Test media: 50 g soybean-paste specimens plus four crumpled balls of toilet paper
- Masses tested: 350, 400, 500, 600, 800, 1,000 g
- Pass = nothing left in the bowl or trap, and a 2-inch trap seal restored
- Score = the highest mass passed in at least four of five attempts
- Third-party testing, not the manufacturer's own claim
How to read the number
A higher score means the toilet moves more in one go. The scale tops out at 1,000 g because the specification forbids testing above it [1] — so a 1,000 g score tells you a fixture reached the ceiling of the test, not how far beyond it it could go.
For an ordinary household bathroom, anything comfortably in the upper range is enough. Where it matters more is a fixture with a long or flat drain run, a rental where nobody is gentle with paper, or a bathroom at the far end of an old line — there, a low-scoring toilet turns into a monthly plunger appointment.
What the score does not tell you
It says nothing about the drain. A 1,000 g toilet on a line with a belly, a root intrusion or a bad slope still blocks. If a toilet that used to work has started blocking, the fixture is rarely the thing that changed.
It says nothing about the bowl wash or how quiet the fill is, and nothing about whether the parts will be available in ten years.
It says nothing about installation. A toilet set on an uneven flange, shimmed badly, or with a wax seal squashed out of position will misbehave whatever its score.
Buying one, practically
Measure the rough-in first — the distance from the finished wall to the centre of the closet bolts, usually 12 inches, sometimes 10 or 14. Then check the MaP score, then decide about one-piece or two-piece, height and shape.
One-piece toilets are easier to clean and heavier to carry. Comfort-height suits most adults; standard height suits small children and shorter adults better than the marketing suggests. Dual-flush saves water only if the household actually uses the small button.
If you buy the fixture, keep the box until it is installed and tested: that is where the bolt caps, the gasket and the instructions live.
What this means in Tampa Bay
Plenty of houses here are on original cast iron or clay laterals, and on those the drain is usually the limiting factor rather than the fixture. If a toilet blocks repeatedly, we would rather put a camera down the line than sell you a better toilet.
We install fixtures customers buy themselves and fixtures we supply, and we reset toilets onto new flanges when the old one has rusted or sunk — which, on a slab house of a certain age, it usually has.
We set it, seal it and test it — and tell you if the flange under it needs work first.
Call 727-470-7126FAQ
Is a higher MaP score always better?
Higher is better up to the point where it stops mattering. The test never goes above 1,000 g, so once a model is in the upper range you are choosing on other things: bowl wash, noise, parts availability, height and shape.
My new toilet blocks. Is it the toilet?
Sometimes, but if the old one on the same drain did not block, look at the drain. A camera inspection of the line shows whether the problem is beyond the toilet.
Do low-flow toilets block more?
Modern ones are tested exactly for this; that is why MaP exists. The drain line and the installation matter more than the gallons per flush.
What rough-in do I need?
Measure from the finished wall to the centre of the bolts holding the toilet down: usually 12 inches, sometimes 10 or 14. Buying the wrong one is a common self-install mistake.
Will you install a toilet I bought?
Yes. Have every part on site, including the supply line, and keep the box.
Sources
We review and cite. We do not reproduce a paper or a manual — follow the links for the originals.
- [1]Maximum Performance (MaP) Testing — Toilet Fixture Testing Specification, Version 7 — MaP Testing · revised 2018Government or standards body · test media, 50 g specimens, four-of-five pass rule, mass intervals to 1,000 g; read in the original 2026-10-01
- [2]MaP Toilet Testing — Background — MaP TestingGovernment or standards body · why MaP was set up (2002, 22 organisations), test-to-failure, score in grams; read 2026-10-01
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