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Toto Home Additions & ADU: The Austin Owner’s Guide
If you’re planning a home addition or ADU in Austin and want Toto fixtures included, the installed price typically runs between $45,000 and $130,000 for the addition itself, with Toto bathroom packages adding $3,500 to $12,000 per bath depending on the fixtures you choose. Homeowners usually reach out to us when they’ve bought a Toto toilet, bidet seat, or washlet system and discovered that their existing plumbing, rough-in dimensions, or electrical setup won’t accommodate it without additional work. That’s the moment when a fixture purchase becomes an addition project, and it’s exactly the kind of work we handle in Austin every week.
We’re an independent Austin remodeling contractor, not a Toto dealer or affiliate. What that means for you is we install and integrate Toto products without pushing you toward one specific showroom or trim package. If you’ve already got the Toto box sitting in your garage, we’ll build around it. If you’re still deciding, we’ll spec the rough-in correctly so any Toto model in the series fits on day one.
Which Toto Models This Applies To
Toto’s product line splits into a few families, and the rough-in requirements differ enough that guessing gets expensive. The Drake, Drake II, and Ultramax lines are 12-inch rough-in gravity-flush toilets that drop into most Austin homes built after 1980 without much fuss. The Washlet and Neorest lines are wall-hung or skirted units that need a carrier system, a dedicated GFCI circuit within 3 feet of the toilet, and often a 1/2-inch supply line upgrade from the old 3/8-inch copper. That last detail is the one that catches people: a 1980s Austin pier-and-beam house with 3/8-inch stops will not run a Neorest properly, and no adapter fixes it. We pull a permit for the supply line, run the circuit, and set the carrier before the drywall ever goes back on.
For OEM versus aftermarket decisions: Toto’s fill valves, flappers, and trip levers are worth buying OEM. The company uses a 2-inch flush valve on Drake models and a 3-inch on Drake II, and aftermarket flappers seat poorly enough that you’ll get ghost flushing within a year. For hardware like supply lines and angle stops, quality aftermarket brass is fine and often better than what came in the box. We stock OEM Toto fill valves, Korky flappers for the 3-inch Drake II valve, and 12-inch stainless braided supply lines on our Austin trucks. If you’re also looking at cabinet or countertop work as part of the addition, we work with KraftMaid, Cambria, and Silestone lines alongside Toto fixtures, so the whole job comes through one crew.
Styles & brands we work with
Signs Your Toto Home Additions & ADU Plan Is Going Sideways
- The rough-in measured 10 inches, not 12. That’s a pre-1990 Austin slab or a pier-and-beam floor with the wall moved at some point. A 12-inch Toto will not fit without an offset flange, and offset flanges on Toto’s skirted bases are notorious for leaking at the wax seal because the base doesn’t cover the offset completely. The fix is moving the flange or reframing, not a thicker wax ring.
- The supply line is 3/8-inch copper and it’s inside a finished wall. Neorest and high-end Washlet models specify a larger volume supply. We open the wall, replace the stub-out with 1/2-inch PEX or copper, and add an accessible shutoff. In Austin’s hard water, the old copper has mineral scaling at the stop, so we replace the stop too, not just the line.
- The bidet seat trips the GFCI every morning. That’s usually a shared circuit problem: the bathroom outlet is tied to the hall, garage, or outdoor receptacles. Toto’s heated seats pull around 1,400 watts at warm-up, and a shared 15-amp circuit can’t hold that plus a hair dryer. The fix is a dedicated 20-amp circuit, which means opening walls. Doing that during an addition is trivial. Doing it after tile is set is expensive.
- The carrier or blocking wasn’t installed for a wall-hung Toto. Wall-hung units need a steel carrier bolted to the floor and wall framing, and it needs to be set before tile and drywall. We’ve fixed several Austin additions where the original contractor roughed it as a floor-mount, and the owner bought a wall-hung Neorest later. That’s a two-day correction, not a swap.
- The subfloor flexes when you walk near the toilet area. Austin’s clay soil moves, and pier-and-beam additions settle. A Toto with a skirted base will crack at the china if the floor flexes, because the base can’t absorb deflection the way a traditional bowl can. We block and reinforce the joists before the toilet ever gets set.
See the difference
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After
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After
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AfterReplacement Cost & What’s Included
For a home addition or ADU in Austin that includes one or two Toto baths, you’re looking at $45,000 to $130,000 for the full addition, depending on foundation type, roofline complexity, and how far we have to run plumbing and electrical. A single Toto bathroom rough-in, including moving a flange, running a dedicated circuit, upgrading the supply line, and setting the fixture, typically adds $3,500 to $12,000 on top of the addition. That range covers the gap between a basic Drake install on an open wall and a wall-hung Neorest with carrier, electrical, and finished tile returns.
We give you a written price before any work starts. That price lists the permit costs, the plumbing and electrical labor, the fixture and trim allowances, and the drywall and paint patch included. If something changes during the job, we tell you the number before we touch it. Every addition carries our 365-Day Done Right Promise: if anything isn’t right within a year of completion, we come back and fix it at no cost to you. The guarantee term is 365 days from the completion date, stated plainly on your contract.
DIY or Call Us?
If you’re swapping a flapper, fill valve, or supply line on an already-installed Toto, that’s a Saturday job with basic tools and you don’t need us. If your project involves moving a toilet flange, opening walls for a dedicated circuit, or setting a wall-hung carrier, call a licensed contractor. The plumbing code in Austin requires a permit for relocating waste lines, and the electrical work on a Washlet or Neorest circuit is covered under NEC 210.11(C)(3), which most homeowners aren’t set up to inspect. Isaac Pruett learned this trade at Los Angeles Trade-Technical College and has seen enough open walls in Austin to know which ones were done right and which ones weren’t.
Tell me what’s wrong with it. We’ll figure out what it actually needs.
Call (903) 623-1966 and we’ll walk the job with you, give you a written number, and tell you exactly who’s coming to your door before they arrive.
FAQs
A Toto toilet’s porcelain will last decades, but the internal components: fill valve, flapper, and trip lever: typically need replacement every 5 to 8 years, sooner in Austin because the hard water from the Edwards Aquifer scales up the fill valve and makes the flapper seat unevenly. Call (903) 623-1966 if you’re replacing components more often than that; there may be a water pressure or sediment issue we should look at.
No. Porcelain cracks in a toilet are not repairable in any way that lasts, and a cracked bowl can fail catastrophically and flood your Austin home. If the crack is in the tank, that’s a parts swap. If it’s in the bowl or base, the entire unit gets replaced. We’ll give you an exact cost before we touch anything.
The plumbing and electrical rough-in for a Toto bathroom, including moving the flange, running the dedicated circuit, and setting the supply line, takes two to three working days in an open-wall addition. Final trim and fixture set takes another day after tile and paint are done. The full addition timeline depends on foundation and framing, and we’ll lay that out for you in writing.
Yes. We carry OEM Toto fill valves, Korky 3-inch flappers for the Drake II series, trip levers, and 12-inch braided supply lines on our trucks, so most repairs are done in one visit. For specialized parts like Neorest carriers or proprietary supply-line pigtails, we can typically source them from our Austin plumbing suppliers in one to two business days. Call (903) 623-1966 and tell us which model you have; we’ll confirm what’s on hand before we schedule.
Written by Isaac Pruett, Owner, Mason Remodeling Co Austin at Mason Remodeling Co Austin, serving Austin and nearby areas.
