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Toto Construction in Ontario, CA | Penhallow Remodeling Riverside
We provide independent Toto service and installation across our Ontario service area, and the one thing that sets our work apart here is simple: we know which Toto fixtures hold up in a 1970s slab home with hard water and which ones are better off replaced before your remodel starts. If you’re planning a bathroom remodel or need a Toto repair in Ontario, we’re the crew that gives you a written number before we pick up a tool, that’s just how this works. Call (341) 895-1170 for a free estimate.
Our team has rebuilt bathrooms and kitchens across Ontario where Toto fixtures were installed by previous owners or builders, so we know how their valve geometry, rough-in dimensions, and mounting systems interact with local remodels and seismic retrofits. We service the full Toto sales & service range independently, which means we source parts and finish work without warranty-flavored upsells. Trevor Nash, our owner, learned his trade at Los Angeles Trade-Technical College and has spent the better part of two decades doing construction across the Inland Empire. His crew has put real hours into Ontario homes, including the older stock near Euclid Avenue where remodelers get honest lessons about what’s behind the walls.
Why Ontario Residents Choose Us for Toto Service

Ontario’s housing stock is largely single-family homes built between the 1950s and the 1980s. Those houses have stucco exteriors, slab foundations, and original galvanized plumbing that’s often corroded from decades of hard water. When a Toto Drake in a 1962 rancher starts ghost flushing at 2 a.m., the problem usually isn’t the toilet’s design, it’s mineral scale on the flush valve seat. We know the difference because we’ve pulled enough of these apart in Ontario bathrooms to recognize the pattern before we even lift the tank lid.
We’re an independent Toto service provider, not manufacturer-affiliated or authorized. That independence matters when a repair bill starts creeping toward replacement cost. We’ll tell you straight whether a new flapper and OEM gasket will fix the issue or whether that cracked Promenade bowl is better off gone. And every job gets the same treatment: a written price before work starts, a defined arrival window, and our 365-Day Done Right Promise in writing. If the work fails inside the guarantee period, we come back and fix it at no charge. A live person answers the phone 24/7, so when you call (341) 895-1170, you reach a real human who can schedule your free estimate.
Styles & brands we work with






Common Toto Construction Problems We Solve in Ontario
Here’s what we see most often in Ontario bathrooms, and why local conditions make each one more likely:
- Ghost flushing on Drake models. The Drake (CST744S/CST744E) uses a flapper that can stretch or degrade over time, but Ontario’s hard water accelerates the problem by scaling the flush valve seat. The flapper stops sealing, water seeps into the bowl, and the tank refills on its own about every 20 minutes. An OEM flapper usually fixes it. An aftermarket one can change the flush pattern and void performance.
- Slow or continuous tank refill on Ultramax II and Vespin II. The fill valve diaphragm in these models (MS604114CEFG and CST474CEFG) clogs with mineral deposits from Ontario’s water. The symptom is a tank that takes forever to fill or never stops running. We replace the fill valve with an OEM part when lead time allows because the flush characteristics stay factory-correct.
- Seeping tank-to-bowl coupling gaskets on Promenade units. Ontario sits in California’s inland seismic zone, and many older slab-on-grade homes have settled enough over 40 or 50 years to put subtle stress on a two-piece toilet’s coupling. The Promenade (CST424SF) has a gasket that can crack or shift after a tremor or years of minor slab movement. Water pools at the base, and that’s never something to ignore on a wood subfloor.
- Corroded soft-close seat hinges. Older Ontario houses often lack bathroom exhaust fans, which means high humidity in a closed space. Combined with cleaning products that get sprayed and left to sit, the hinges on Toto’s soft-close seats corrode faster than you’d expect. We replace them with OEM hinge assemblies, not whatever the hardware store has in a blister pack.
- Cast iron flange rot on pre-1985 installations. This one is almost unique to Ontario’s older neighborhoods. Homes along Euclid Avenue and in the historic downtown core often have original Toto toilets hard-piped to cast iron stacks. The flange rusts, the toilet rocks, and wax seals fail repeatedly. We sleeve the drain, reset the toilet with a wax-free seal, and stop the problem at the source.
Toto Service in Ontario: What Local Conditions Mean for Your Equipment

Ontario’s pre-1985 homes along Euclid Avenue and downtown were built differently than anything going up in the northern and eastern expansion areas today. Those older houses often have 1.6 gpf or older Toto toilets hard-piped to cast iron stacks, which means any remodel that touches the bathroom may require opening a wall or slab to address the drain connection. Our General Contractor in Ontario sees what contractors who mostly work in newer Inland Empire subdivisions rarely encounter, because newer builds tie into ABS or PVC with standard flanges. In an older Ontario house, the stack itself may be rusted through at the floor line, and the toilet’s rough-in may not match what a modern Toto expects. That’s the kind of thing you want someone to spot before demolition starts, not after the tile is up.
On a 1972 ranch near Euclid and G Street, we completed a Bathroom Remodeling in Ontario project, converting a tub alcove to a walk-in shower for a homeowner who had an original Toto Ultimate toilet in the same bathroom. The cast iron flange had corroded from years of hard water and minor slab movement, so our tech sleeved the drain and reset the toilet with a new wax-free seal, then finished the shower with a frameless enclosure. The toilet flushed better than before and the whole remodel came in under three weeks. That’s the Ontario reality: old plumbing, hard water, and a floor that’s moved a little over five decades. Work with it, and the results hold up.
Toto Models & Products We Service in Ontario
We service the Toto Drake (CST744S/CST744E), Ultramax II (MS604114CEFG), Promenade (CST424SF), and Vespin II (CST474CEFG), along with older Toto lines still running in Ontario homes. Our approach to parts is straightforward: for repairs, we use OEM gaskets, flappers, and fill valves when lead time allows, because aftermarket parts often change flush characteristics or void performance. For faucet trim and showerheads, quality aftermarket cartridges from Delta or Kohler work well. If a Toto one-piece toilet has a cracked trapway or bowl, replacement usually costs less than the labor to properly seal and refinish it. We keep common OEM repair parts on hand for faster turnaround in Ontario, and anything we don’t stock is usually in within a few days.
See the difference
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AfterToto Service Pricing in Ontario

Here’s what you can expect for the most common Toto-related jobs in Ontario:
| Service | Price Range |
|---|---|
| Bathroom Remodel | $9,000 – $28,000 |
| Tub-to-Shower Conversion | $3,500 – $10,000 |
| Walk-In Shower Installation | $4,500 – $12,000 |
| Bathroom Vanity Installation | $800 – $3,000 |
What drives the number up or down? The age of your Ontario home, for one. A cast iron stack replacement adds more to a job than a toilet swap in a newer build. The condition of your subfloor after years of hard water exposure matters too. A free estimate from us includes a written line-item quote, not a verbal range, so the number on day one is the number on the invoice. Call (341) 895-1170 to schedule yours, and we’ll walk you through exactly what we’d do in your bathroom.
Serving Ontario, CA - Our Local Coverage Area
We’re based in the Ontario area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs — Toto Construction in Ontario
Yes, especially in pre-1985 homes along Euclid Avenue and downtown. Many older Ontario bathrooms were plumbed for a 10-inch or even 14-inch rough-in, while modern Toto toilets are typically built for a standard 12-inch rough-in. If your existing Toto sits at a different measurement, moving the drain line in a slab foundation adds labor and cost. We check the rough-in before any tile or drywall comes out, so there are no surprises mid-job. Call (341) 895-1170 for an exact quote, estimates are free.
Ghost flushing on Toto Drake models tops the list. Ontario’s water leaves mineral deposits on the flush valve seat, which prevents the flapper from sealing completely. The toilet then refills itself on and off all day and night. It’s usually a straightforward OEM flapper and seat cleaning, and we can have it done in a single visit. Call (341) 895-1170 to schedule a repair, and we’ll give you a written price before we start.
If it’s a Drake, Ultramax II, or Vespin II in good structural condition, we’ll often reuse it. If it’s an original Toto from before 1985 with a corroded cast iron flange or a hairline crack in the trapway, replacement usually costs less than the labor to properly seal and refinish it. We’ll tell you which path makes sense before demolition starts, and the recommendation will come with a written number either way.
It affects how we anchor and seal them. Ontario homes in older neighborhoods may carry unreinforced masonry or have settled slab-on-grade foundations, and a toilet that shifts during a tremor or ground movement will crack the coupling gasket or break the wax seal. We use wax-free seals and proper anchoring on every Ontario installation, and we check the floor for movement before we set the toilet. It’s a small step that prevents a much larger repair later.
Toilet replacement typically falls within the bathroom remodel line item of $9,000 to $28,000, depending on how much plumbing access your slab foundation requires and whether the flange needs sleeving. A simple swap in a newer Ontario home keeps the number low. A cast iron stack repair in an older home pushes it higher. Call (341) 895-1170 for an exact quote, estimates are free.
Service Areas Near Ontario
We cover Ontario and surrounding communities across the Inland Empire, including Toto service in Riverside, Toto service in Anaheim, San Bernardino, Claremont, and Menifee. If you’re in any of these areas, call us, we’ll give you the same written price and 365-Day Done Right Promise.
Book Your Toto Service in Ontario Today
If your Toto toilet is ghost flushing, your bathroom remodel is coming up, or you just want a written number before deciding anything, call (341) 895-1170. A live person answers 24/7, and your estimate is free. We’ll show up in the window we gave you, put the price in writing, and stand behind the work for a full year.
Written by Trevor Nash, Owner at Penhallow Remodeling Riverside, serving Ontario and the Inland Empire.












