Toilet Tank Replacement Kit Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Fluidmaster is the best-performing toilet tank replacement kit brand in July 2026, moving 28,000 units across 4 ASINs for 43.8% of Top 10 volume. Korky follows with 15,000 units (23.4%), ahead of Hibbent on 13,000 units (20.3%).

With 4 brands splitting the Top 10 and 87.5% of volume sitting with three of them, this is a concentrated shelf — the leaders hold multiple listings or one very high-velocity ASIN, so a new entrant competes against established review moats rather than an open field. Average selling prices among the leaders run from $8.48 to $17.52, which frames the price band a competing listing has to justify.

Based on July 2026 data, this shortlist surfaces the two kinds of ASIN worth keeping an eye on — the ones that just broke into the Top 10, and the ones growing fastest month over month. Specifically, one ASIN forced its way in: B003MH314U booked 2K units at $20.48, with ▲ 100.0% MoM change. On the growth side, B014ENSA7I leads positive momentum with ▲ 900.0% MoM growth on 500 units, with B07T8KCX9G close behind at ▲ 300.0% MoM on 400 units.

The two signals carry different weight. A fresh entrant means share has already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date. A steep growth rate works as the earlier warning: it marks demand that is still compounding, usually a month or two before the ranking catches up to it.