TLDR Review: Fluidmaster K-400H-039 Toilet Fill Valve and Flapper Kit
Verdict
If you're looking for a straightforward toilet fill valve and flapper kit that’s easy to install and effectively solves running toilet problems while improving flush strength, the Fluidmaster K-400H-039 is a reliable choice. Just be sure to measure your flush valve opening beforehand and be aware the included tube might need swapping if it interferes with your toilet’s flush lever. For those who want a super long-lasting solution or faster refill speeds, consider evaluating other premium models, but for solid value and performance, this kit hits the mark.
- Top pro:
- Easy and quick installation with clear, easy-to-follow instructions suitable even for beginners and DIY enthusiasts
- Top con:
- The connecting tube is shorter than some previous models and may interfere with the flush lever, sometimes requiring a replacement tube
Pros
- •Easy and quick installation with clear, easy-to-follow instructions suitable even for beginners and DIY enthusiasts
- •Adjustable 2-inch flapper allows for fine-tuning flush performance and water flow
- •Provides a stronger, more effective flush with reliable positive shut-off to prevent running water waste
- •Quiet operation with smooth fill valve performance, eliminating annoying running noises
- •Comes as a complete kit including all necessary parts for a full toilet repair or upgrade
- •Reliable sealing that effectively stops leaks and running toilet issues
- •Compatible with braided supply lines for increased installation stability
- •Suitable for multiple uses with consistent quality reported across several purchases
- •Valve height and flow adjustments are straightforward and user-friendly
Cons
- •The connecting tube is shorter than some previous models and may interfere with the flush lever, sometimes requiring a replacement tube
- •The adjustable valve can occasionally leak a tiny stream of water at certain settings, though it usually does not cause significant problems
- •Slightly slower refilling speed compared to older models
- •Build quality is decent for the price but not expected to last for decades; some users may want a longer-term solution
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How we researched this
About this review: it summarizes the professional reviews and customer ratings ShopSavvy collected for this product, alongside prices from 15 retailers in ShopSavvy's price data, most recently seen Oct 10, 2026.
Where to Buy
| Retailer | Price | Last seen | Buy |
|---|---|---|---|
| $15.73 | Jan 25, 2025 may have changed | ||
| $15.98 | Sep 19, 2024 may have changed | ||
| $16.97 | Oct 10, 2026 | ||
| $16.98 | Jan 25, 2025 may have changed | ||
| $17.19 | Sep 19, 2024 may have changed |
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