Is flush valve seal profitable to sell on Amazon United States?

The niche generates $68K/yr across 19 tracked products. 1 of 4 products launched in the last 360 days are still selling. 90-day search growth is +16.1%. Flapen's verdict: Worth a look (51/100).

How competitive is the flush valve seal niche?

14 brands and 85 sellers compete. The top 5 products take 59% of clicks and top 5 brands hold 76% of demand.

What do buyers complain about in flush valve seal?

Top complaints mined from reviews: Leak-Proof, Noise Level, Durability. The return rate is 2.4%.

When does demand for flush valve seal peak?

Demand peaks in Aug; the busiest month runs 1.7× the quietest.

What does it cost to enter the flush valve seal niche?

Listings span $4.53–$36.21; the average listing price is $9.88 (sweet spot $15–$100). The average incumbent carries 1,191 reviews — the moat a new listing must climb.

flush valve seal

Worth a look

Shows searches that convert (8.7% search→purchase), but a small market ($68K/yr) keeps it on the watch list.

Conversion

Great8.7%

search→purchase rate — share of searches ending in a sale

Quality gap

Great4.2★

avg incumbent rating — lower means beatable quality

Price range

Good$4.53–$36.21

cheapest to priciest tracked listing — scored on the share inside $15–$100

Returns

Good2.4%

return rate — above 5% kills the launch gate

Review moat

Good1,190.89

avg incumbent reviews — the moat a new listing must climb

Brand share

Okay76%

top-5 brand share — brands hold most of the demand

Growth

Okay+16.1%

90-day search growth — must beat 0% to launch

Competition

Okay59%

top-5 click share — leaders hold, buyers still browse

Avg price

Okay$9.88

avg listing price — sweet spot $15–$100

Market size

Bad$68K

$68K/yr · 80K searches

Signals Low Review Barrier

According to Flapen's Amazon United States niche tracking, flush valve seal is a $68K/yr Amazon United States market (80K searches/yr). The top 5 brands hold 76% of demand. Demand peaks in Aug. Verdict: Worth a look — 51/100.

Data updated Jul 27, 2026 · scored weekly · How we score niches

flush valve seal market data

Units sold / yr: 6K–8K; avg 100–250/product
Revenue / yr: $59K–$79K; units × avg price
Conversion rate: 8.7%
Avg BSR: #2,694
Page quality: 0%
Prime: 89%
Sponsored: 84%
Out of stock: 5.0%
Avg brand age: 27 months
Avg seller age: 153 days

Competition & brand share

The top 5 products take 59% of clicks — established leaders, but buyers still shop beyond them.

Brands

14 falling

Sellers

Top-5 brand share

76%

Top 20: 100%

Top-5 click share

59%

Top 20: 100%

Open market

19%

HUTUDAN27%
Fluidmaster20%
Ruinuonice11%
CTEAKOP11%
TOHAXPLS6%
Kohler5%

Demand & seasonality

Weekly Amazon search volume, last 100 weeks — +16.1% search growth over the last 90 days.

Peak months: Aug · busiest ÷ quietest = 1.7×

Open Trend

Top flush valve seal search terms

toilet fill valve seal24K/yr +13.1%6.4% conv.
fluidmaster 242 toilet fill valve seal9K/yr +8.2%10.3% conv.
fluidmaster 2428K/yr +39.4%7.5% conv.
toilet valve seal8K/yr +15.2%5.0% conv.
fluidmaster toilet fill valve seal11K/yr -19.5%6.9% conv.
fluidmaster fill valve seal4K/yr +63.4%6.4% conv.
kohler fill valve seal4K/yr +19.0%8.3% conv.
fill valve seal5K/yr +15.8%8.8% conv.
fluidmaster seal3K/yr +38.4%3.8% conv.
toilet fill valve seal replacement3K/yr +60.0%7.6% conv.

All search terms

Top flush valve seal products on Amazon

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 19 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

3 Pack Toilet Fill Valve Seal replacement for Kohler 83143 - Compatible with Fluidmaster 200/242/400/747 Models - Durable Rubber Diaphragm Assembly for DIY Leak Prevention & Tank Repair

HUTUDAN$6.614.2★97 rev

CTEAKOP 2 Pcs Black Toilet Fill Valve Seal Replacement Part Rubber Toilet Parts Inside Tank Kit Flush Valve Seal for Fluidmaster 200 747 and 400 Models Toilet Fill Valve

CTEAKOP$5.974.1★70 rev

Ruinuonice Toilet Fill Valve Seal Replacement Part for Kohler 83143 - Compatible with Fluidmaster 242/400/747 - Rubber Diaphragm Assembly for DIY Toilet Tank Repair & Leak Prevention (Black-1Pack)

Ruinuonice$5.393.9★66 rev

Fluidmaster 242 Toilet Fill Valve Seal Replacement Part Fits 400A Fill Valve (10)

Fluidmaster$22.804.6★172 rev

Fluidmaster 400H-002 Performax Universal Toilet Fill Valve High Performance Tank and Bowl Water Control 1-Pack Multicolor

Fluidmaster$14.894.6★16,896 rev

Newest

by launch date

3 Pack Toilet Fill Valve Seal replacement for Kohler 83143 - Compatible with Fluidmaster 200/242/400/747 Models - Durable Rubber Diaphragm Assembly for DIY Leak Prevention & Tank Repair

HUTUDAN$6.6197 rev

8mo ago

Waziaqoc 2 Pcs Toilet Fill Valve Seal Replacement

Waziaqoc$5.227 rev

9mo ago

6 PCS 83143 Toilet Fill Valve Seal Replacement - Compatible with Fluidmaster-200/242/400/747 Black Rubber Toilet Fill Valve Seal Replacement Part Durable Toilets Tank Part Diaphragm

Pretwad$6.9533 rev

11mo ago

For Kohler Fluidmaster Toilet Fill Valve Seal Kit

Azanxo$7.888 rev

11mo ago

83143 Toilet Fill Valve Seal 2 Pack Fit for Kohler Fluidmaster

ZanFyxil$8.3312 rev

1y ago

What buyers say about flush valve seal

What buyers praise and complain about, mined from review topics.

What buyers love

Assembly/Installation31%

“Easy fix”

Efficiency8%

“Works great”

Value For Money7%

“Good price”

Size-Overall7%

“Fit well”

Advertised Vs Actual Product6%

“As advertised”

Ease Of Use6%

“Easy as pie”

Quality-Overall6%

“The build quality feels solid”

Instructions/User Manual/Troubleshooting5%

“Instructions are clear”

Maintenance And Repair2%

“Easy fix”

Adjustability/Rotatability/Reclining2%

“Very adjustable”

What buyers complain about

Leak-Proof18%

“leaking in to the tank”

Noise Level13%

“Random noises”

Durability8%

“broke almost instantly”

Size-Overall8%

“it was very tight inside the tank”

Functionality-Overall7%

“Did not function”

Quality-Overall5%

“Garbage”

Compatibility-Overall4%

“Perhaps it wasn't fully compatible”

Value For Money3%

“Not what we were expecting for the price”

Product Condition3%

“Used. Arrived used. Was cleaned”

Design-Overall2%

“Good product bad nut design”

Top return reasons

Size-Overall29%

Leak-Proof16%

Functionality-Overall11%

Defective Material/Parts11%

Compatibility-Overall8%

Value For Money5%

Advertised Vs Actual Product4%