One piece toilets are sleek, modern, and easier to clean than traditional two-piece designs. But when the fill valve fails, you may notice problems like constant running water, noisy refills, or weak flushes. Because of their compact design, one piece toilets sometimes require fill valves with a lower profile or specific adjustments. Choosing the best fill valve for a one piece toilet ensures proper performance, quiet operation, and a perfect fit. In this guide, we’ll highlight the top fill valves for one piece toilets, explain what to look for, and answer common questions.
Quick Picks
- Best Overall: Korky 528MP QuietFill Platinum Fill Valve – Compact, quiet, and adjustable to fit one piece toilets.
- Best Budget: Fluidmaster 400A Universal Fill Valve – Affordable, universal design that works with most one piece toilets.
- Best Premium: Toto TSU99A.X Adjustable Fill Valve – OEM reliability for Toto one piece toilets, very quiet and efficient.
Buyer’s Guide: Choosing a Fill Valve for One Piece Toilets
When buying a replacement valve for a one piece toilet, consider these important factors:
- Compact design: One piece toilets often have less space inside the tank, so low-profile or adjustable valves are best.
- Quiet operation: Since one piece toilets are often in master bathrooms, noise reduction is key.
- Adjustability: Height-adjustable fill valves (7″–14″) work with different tank sizes.
- OEM compatibility: If you own a Toto or Kohler one piece toilet, an OEM valve is often the safest choice.
- Ease of installation: Look for DIY-friendly valves that can be installed in under 30 minutes.
Detailed Product Reviews
Korky 528MP QuietFill Platinum Fill Valve
Best Overall
The Korky 528MP is designed with one piece toilets in mind. It’s compact, adjustable, and features QuietFill technology for near-silent operation.
- Height adjustable: 7.75″–13.5″
- Universal compatibility
- Made in the USA with premium materials
Pros: Quiet, compact, long-lasting
Cons: Costs slightly more than basic valves
Verdict: The best all-around option for one piece toilets. Check price here.
Fluidmaster 400A Universal Fill Valve
Best Budget
The Fluidmaster 400A is the most popular universal fill valve in the U.S. It fits most one piece toilets and provides reliable performance at a low cost.
- Adjustable height: 8″–14″
- Anti-siphon design for safety
- Proven reliability in millions of toilets
Pros: Inexpensive, widely available, dependable
Cons: Louder than quiet-fill models
Verdict: Best budget-friendly choice. See it on Amazon.
Toto TSU99A.X Adjustable Fill Valve
Best Premium
The Toto TSU99A.X is an OEM replacement part designed for Toto toilets, including many one piece models. It’s quiet, efficient, and perfectly matched to Toto systems.
- Designed specifically for Toto one piece toilets
- Adjustable to fit various tank sizes
- OEM reliability and quiet performance
Pros: OEM fit, very quiet, long-lasting
Cons: More expensive than universal valves
Verdict: Best premium choice for Toto owners. View today’s price.
Comparison Table
| Product | Best For | Adjustable Height | Noise Level | Price Link |
|---|---|---|---|---|
| Korky 528MP | Overall performance | 7.75″–13.5″ | QuietFill, very quiet | View Price |
| Fluidmaster 400A | Budget option | 8″–14″ | Moderate noise | View Price |
| Toto TSU99A.X | Toto one piece toilets | Custom adjustable | Very quiet | View Price |
FAQ
Do one piece toilets need special fill valves?
Some one piece toilets have compact tanks that require low-profile or OEM-specific fill valves. Universal adjustable valves often work as well.
What’s the quietest fill valve for one piece toilets?
The Korky 528MP and Toto TSU99A.X are among the quietest options available.
How do I know if a fill valve fits my one piece toilet?
Check the manufacturer’s recommendations in your toilet’s manual. OEM parts guarantee compatibility, but many universal valves also fit.
Can I replace a fill valve myself?
Yes. Most fill valves install in 20–30 minutes with basic tools. One piece toilets may require more care due to compact tank space.
How long does a fill valve last?
Most last 5–7 years. Hard water and high usage may shorten lifespan.
Conclusion & Call-to-Action
Finding the best fill valve for a one piece toilet ensures smooth, quiet refills and reliable flushing performance. For most households, the Korky 528MP QuietFill is the ideal balance of quiet operation and compact design. For budget shoppers, the Fluidmaster 400A is a proven universal option. And for Toto one piece toilet owners, the Toto TSU99A.X provides the best OEM performance.
Order your one piece toilet fill valve today and restore quiet, efficient performance to your bathroom.