Gerber 21-910 Maxwell Toilet Review: Efficient & Reliable

Looking to upgrade your bathroom with a toilet that saves water and performs flawlessly? You’re not alone. Many U.S. homeowners struggle to find a balance between efficiency, comfort, and installation compatibility—especially in older homes with tighter spaces. The Gerber Plumbing 21-910 Maxwell 1.28 GPF Two-Piece 10 Inch Rough-In toilet offers a smart solution: high-performance flushing with ultra-low water use, designed specifically for compact bathrooms. Let’s dive into why this model stands out in today’s eco-conscious market.

What Is the Gerber 21-910 Maxwell Toilet?

The Gerber 21-910 Maxwell is a two-piece, gravity-flush toilet built for residential use. It features a 1.28 gallons per flush (GPF) rating—well below the federal standard of 1.6 GPF—making it WaterSense® certified by the U.S. Environmental Protection Agency (EPA). Its 10-inch rough-in design caters to older homes or smaller bathrooms where space is limited, a key differentiator from the more common 12-inch rough-in models.

Unlike many budget toilets, the Maxwell series combines Gerber’s century-old plumbing expertise with modern engineering. Founded in 1932, Gerber has long been trusted by contractors and DIYers alike for durable, code-compliant fixtures.

💡 Did You Know? Toilets account for nearly 30% of indoor household water use, according to the U.S. Geological Survey. Switching to a 1.28 GPF model like the Gerber 21-910 can save up to 4,000 gallons of water per year for a family of four.

Why Choose a 10-Inch Rough-In Toilet?

Most new constructions use a 12-inch rough-in (the distance from the wall to the center of the drainpipe). But homes built before the 1980s often have 10-inch or even 14-inch rough-ins. Installing a standard 12-inch toilet in a 10-inch space leaves an unsightly gap or requires costly plumbing rerouting.

The Gerber 21-910 Maxwell solves this problem by fitting snugly against the wall in 10-inch setups—no modifications needed. This makes it ideal for:

• Historic home renovations
• Powder rooms with tight layouts
• Basement or half-bath remodels

✅ Pro Tip: Always measure your rough-in before buying! Measure from the finished wall (not baseboard) to the center of the closet bolts. Round to the nearest standard size (10″, 12″, or 14″).

Performance & Water Efficiency: Does It Really Work?

One common concern with low-flow toilets is weak flushing. But the Gerber 21-910 Maxwell defies that myth.

It uses Gerber’s AquaPak® flushing technology, which optimizes trapway design and water velocity for a powerful, single-flush clean. Independent tests by Consumer Reports and plumbing professionals show it consistently clears solid waste in one flush—a critical benchmark for real-world usability.

📊 MaP (Maximum Performance) Testing evaluates how much solid waste a toilet can remove in one flush. A score of 350+ grams is considered good; 1,000+ is exceptional. The Gerber Maxwell exceeds expectations here.

For context, the average human waste output per bowel movement is 100–200 grams. A 1,000g MaP score means this toilet can handle 5+ full loads in one go—far beyond daily needs.

Installation Guide: Step-by-Step for DIYers

Installing the Gerber 21-910 is straightforward if you’re comfortable with basic plumbing. Here’s how:

1. Turn off water supply and disconnect the old toilet. Remove wax ring residue.
2. Inspect flange: Ensure it’s level with or slightly above the finished floor. Replace if cracked.
3. Install new closet bolts into the flange slots (included with toilet).
4. Place wax ring (or wax-free alternative) on the flange.
5. Lower tank and bowl onto bolts—align carefully to avoid leaks.
6. Secure with nuts, but don’t overtighten (porcelain can crack).
7. Attach tank to bowl using included hardware (two-piece design).
8. Reconnect water supply, turn on, and check for leaks.
9. Test flush 3–5 times to ensure proper seal and function.

⚠️ Note: Use a reinforced wax ring if your flange is below floor level. For extra peace of mind, consider a wax-free seal like the Fluidmaster Better Than Wax.

Total install time: 45–90 minutes for most DIYers.

Pros and Cons at a Glance

✅ Advantages

• Saves ~4,000 gallons of water/year vs. older 3.5 GPF models
• Fits 10-inch rough-in spaces without remodeling
• Comfort-height elongated bowl (ADA-compliant)
• Quiet, gravity-fed flush (no noisy pressure assist)
• Affordable ($200–$280 retail)

❌ Limitations

• Two-piece design requires more assembly than one-piece
• Seat not included (budget $20–$40 extra for soft-close)
• Limited color options (typically white only)

How It Compares to Competitors

As you can see, the Gerber 21-910 is the only major brand offering a high-performance 1.28 GPF toilet with a 10-inch rough-in—making it uniquely valuable for specific installations.

Sustainability & Long-Term Value

Choosing a WaterSense-certified toilet isn’t just eco-friendly—it’s economical. The EPA estimates that WaterSense toilets save the average household $110+ per year in water and sewer costs.

Plus, Gerber backs the 21-910 with a limited lifetime warranty on porcelain and 5-year warranty on mechanical parts—a strong vote of confidence in its durability.

For deeper insights into water conservation standards, see the EPA’s WaterSense program overview on Wikipedia.

FAQ Section

Q1: What does “10-inch rough-in” mean?
A: It’s the distance from the finished wall to the center of the toilet drainpipe. Most homes use 12″, but older ones may have 10″ or 14″. Measuring correctly prevents fit issues.

Q2: Is the Gerber 21-910 ADA compliant?
A: Yes. With a 16.5-inch seat height (without seat), it meets ADA guidelines for “comfort height” toilets (17–19″ with seat).

Q3: Does it come with a seat?
A: No. You’ll need to purchase a standard elongated toilet seat separately. Soft-close models are recommended for noise reduction.

Q4: Can I install it myself?
A: Absolutely—if you’ve replaced a toilet before. The two-piece design is lighter and easier to maneuver than one-piece models. Just follow the steps above and take your time.

Q5: How much water does it really save?
A: Compared to a pre-1994 3.5 GPF toilet, the 1.28 GPF Maxwell saves 2.22 gallons per flush. At 5 flushes/day, that’s 4,050 gallons/year—enough to fill a small swimming pool!

Q6: Is it noisy when flushing?
A: No. It uses a quiet gravity flush, unlike pressurized or dual-flush systems that can sound like a jet engine. Ideal for powder rooms near living areas.

Conclusion

The Gerber Plumbing 21-910 Maxwell 1.28 GPF Two-Piece 10 Inch Rough-In toilet delivers exactly what discerning homeowners need: water efficiency, reliable performance, and space-saving design—all at a reasonable price. Whether you’re renovating a vintage bungalow or optimizing a tiny half-bath, this model removes the guesswork and guess-flushes.

If you’ve been frustrated by ill-fitting or underperforming toilets, the Maxwell could be your perfect match.

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