Toto Home Additions & ADU Nationwide

Toto Home Additions & ADU: The Huntington Beach Owner’s Guide

We stock and install Toto plumbing fixtures and rough-in components for home additions and ADU projects in Huntington Beach, with installed pricing typically running $45,000-$130,000 for the full addition and $90,000-$220,000 for detached ADU construction. Toto fixtures are specified in about a third of the ADU plans we bid here, especially the Drake and Ultramax II series, and we carry the common flush valves, fill valves, and rough-in flanges on our trucks. Most owners discover a Toto component issue mid-project, when a rough-in doesn’t line up with the slab pour or when a fixture spec from the architect doesn’t match the actual drain location in a converted garage.

Call (657) 288-3368

Which Toto Models This Applies To

The Toto fixtures we see most often in Huntington Beach additions and ADUs fall into three series: the Drake (CST744E, CST454CEFG), the Ultramax II (MS604114CEFG), and the entry-level Entrada (CST243EF). Each uses a different rough-in dimension and flange height, which matters when you’re pouring a new slab or sistering joists in a second-story addition. The Drake and Ultramax II both use Toto’s 3-inch flush valve, but the Ultramax II ships with the SoftClose seat and a skirted trapway that changes the footprint by about two inches. That’s the gotcha we’ve hit twice on Bolsa Chica projects where the architect spec’d the Drake and the homeowner upgraded mid-permit.

To identify your part, check the stamped model number inside the tank lid or on the trapway label behind the bowl. For rough-in components, the flange height is stamped on the PVC collar. We source OEM Toto parts through our regular supplier, though we also stock Korky and Fluidmaster equivalents for fill valves when the lead time on Toto-branded units runs past the inspection date. The OEM flush valve is worth waiting for; the fill valve is not.

Signs Your Toto Home Additions & ADU Is Failing

• Phantom flushes or tank refilling every 20 minutes. The flapper or flush valve seal is degrading. In Huntington Beach, the chloramine treatment in city water hardens rubber faster than chlorine alone, so we see this at 4-6 years instead of the 8-10 Toto publishes.
• Weak flush that requires a second press. The 3-inch flush valve chain has stretched or the valve seat has mineral buildup. The Drake’s G-Max system depends on that full 3-inch drop; even a quarter-inch of scale cuts the flush volume enough to matter.
• Water pooling at the base after installation. The wax ring compressed unevenly or the flange sits below the finished floor. In ADU garage conversions with thin-set tile over concrete, the flange often ends up recessed, which Toto’s skirted bowls tolerate poorly.
• Tank wobbles or shifts when leaned on. The mounting bolts are loose or the china bolt holes have hairline cracks. We caught this on a Pacific Coast Highway job where the homeowner had tightened the bolts with a socket wrench and cracked the tank.
• Fill valve hisses continuously. The diaphragm or float cup has debris in it. Huntington Beach’s water pressure runs 65-85 PSI in most zones, which is above Toto’s 80 PSI recommendation and accelerates fill valve wear.

Before

After

Replacement Cost & What’s Included

What drives the range: flange resets cost more when the subfloor is rotten or the concrete needs coring, which we find in about one in five Huntington Beach garage conversions where the original slab was poured without a vapor barrier. Under Clause 1 of The Haven Standard, every Toto fixture replacement gets a written price before we start, and the 365-Day Done Right Promise covers the workmanship. We don’t charge separately for the photo record; it’s included on every visit.

DIY or Call Us?

What you can safely check: the water supply shutoff, the tank bolt tightness (finger-tight only), and whether the flapper chain has too much slack. These take five minutes and a towel.

Where DIY goes wrong: over-tightening tank bolts cracks china. Using a standard wax ring on a recessed flange in a garage conversion guarantees a future leak. And if you’re cutting concrete to reset a flange, you’re in permit territory, Huntington Beach requires a plumbing permit for any subfloor or slab penetration in an ADU. The fill valve replacement looks simple until the old shank snaps off in the tank because it’s fused to the nut.

We’re not affiliated with Toto; we’re an independent contractor that installs their fixtures to spec. If your addition or ADU project has a Toto compatibility question, call (657) 288-3368 and we’ll walk through the model number and rough-in before you schedule.

FAQs