Fast, Reliable Bathroom Remodeling Across Ontario
Bathroom remodeling in Ontario, CA typically costs $12,000 – $28,000 for a full gut renovation in the city’s 1950s – 1970s tract homes, and most projects we take on run four to eight weeks from demo to final inspection. That range covers the reality of Ontario’s older housing stock: cast-iron drain lines, undersized sewer laterals, and hard-water corrosion that newer cities rarely deal with. We’re Sunstone ADU Builders, led by Nate Holloway, and we work throughout Ontario every week, from the neighborhoods off Euclid Avenue to the newer subdivisions east of the 15. Call (855) 949-1913 for a free estimate that accounts for what’s actually under your slab, not a generic number.
Why Sunstone ADU Builders Is Ontario’s Preferred Bathroom Remodeling Company
Most Ontario bathroom remodels we see start the same way: a homeowner tears out a 1960s pink tile bathroom, opens the wall, and finds galvanized supply lines that look like clogged arteries. That’s the moment local experience stops being a talking point. Our Bathroom Remodeling team has handled dozens of these mid-century bathrooms across Ontario, and we know what’s behind the walls before we open them. Homes in ZIPs 91761 and 91762 were built in the same decade with the same materials, which means we can usually tell you what you’ll find during the walkthrough, not after demo starts.
Nate Holloway runs every Ontario project personally. That means the person you talk to on the phone is the same person who signs off on the sewer lateral inspection and the final tile walkthrough. Our Ontario customers routinely tell us the thing they didn’t expect was not being handed off to a rotating cast of subcontractors. The plumber we use in Ontario knows the city’s older drain configurations. The inspector conversations happen in person at the Ontario permit counter, not over email from a remote office.
We’re not a general contractor squeezing in bathroom remodels between kitchen jobs. Bathrooms inside Ontario ADUs are one of our core scopes, which means the plumbing, waterproofing, and ventilation decisions are made by people who think about them every single week, in this city specifically.
Our Bathroom Remodeling Services in Ontario
Full Bathroom Remodel
We gut Ontario bathrooms down to the studs and rebuild them around what we actually find: galvanized supply lines, crumbling cast-iron drains, and water-damaged framing that’s been hidden behind tile since the Eisenhower administration. The result is a bathroom that’s sealed against Ontario’s hard water and ready for another fifty years. Most full remodels in Ontario run $14,000 – $28,000 depending on whether we’re fixing infrastructure or just updating finishes.
Shower and Tub Replacement
Ontario’s hard water chews through builder-grade chrome and pot-metal drains fast. We spec brushed nickel or matte black fixtures with ceramic disc valves, solid brass drain assemblies, and a sealed cement board system behind every shower wall. If you’re replacing a tub with a walk-in shower in an Ontario home, we’ll check the existing drain line capacity before we order a single tile, because a 1950s 1.5-inch line may not pass a modern 2-inch shower drain requirement.
Vanity and Fixture Upgrades
A vanity swap in Ontario is rarely just a vanity swap. The shutoff valves under the sink are often seized, the supply lines are galvanized, and the p-trap is a corroded mess. We replace the shutoffs, the supply lines, and the drain assembly while the vanity is out, using solid brass components that won’t pit in Ontario’s mineral-heavy water. Vanity and fixture projects are the most affordable bathroom work we do in Ontario, typically $3,500 – $8,000.
ADU Bathroom Build-Outs
This is where we’re different, and it matters in Ontario. Bathroom remodels inside detached ADUs in this city carry a specific risk: the original sewer lateral was sized for a 3-bed/2-bath house, not an extra bathroom in the backyard. We pressure test the lateral before we set a single fixture. In the older Ontario tracts with alley access, particularly off Holt Boulevard, we can often re-route drains independently without trenching through the main house’s foundation. That’s a cost saver and a permitting simplicity most builders don’t know to look for.
What happens when you call
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A real person answersNo phone trees — you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Ontario
Sunstone ADU Builders is an authorized builder and installer for prefab ADU brands including Cover, Dvele, and Mighty Buildings. When an Ontario homeowner chooses a prefab ADU shell, the bathroom interior still needs to be finished to match the main house, and that’s our in-house scope. We’re also specifying James Hardie fiber cement siding on the exterior of these units, which handles Ontario’s Santa Ana wind events and hot inland summers far better than vinyl. If you’re bringing in a Boxabl or Abodu unit, we handle the bathroom build-out inside it, including the drain connections that Ontario’s older properties need.
Common Bathroom Remodeling Problems We See in Ontario Homes
- Undersized sewer laterals in ADUs. In Ontario’s mid-century tract neighborhoods across ZIPs 91761 and 91762, the original clay laterals were sized for a three-bedroom house, not a house plus a detached ADU bathroom. Adding a shower and second sink without testing the lateral first leads to sewage backups and a far more expensive repair later.
- Hard-water corrosion on builder-grade fixtures. Ontario’s municipal water has aggressive mineral content that pits chrome faucets and pot-metal drains within two years. We’ve pulled out two-year-old fixtures in Ontario bathrooms that look like they’ve been there for two decades.
- Unsealed cement board and standard drywall around tubs. The combo of Ontario’s hot summers and mineral-heavy water accelerates efflorescence and mold growth in any joint that isn’t properly sealed. We use a full waterproof membrane system, not just green board, on every Ontario shower.
- Root intrusion in the alley-side drain lines. In the older blocks off Euclid Avenue where ficus trees line the alleys, roots invade the shallow clay laterals. We pressure test every line before we spend a dollar on tile.
Pricing for Bathroom Remodeling in Ontario, CA
Here’s what we’re quoting in Ontario right now, based on actual projects across 91761, 91762, 91764, and 91758:
- Vanity and fixture upgrade: $3,500 – $8,000
- Shower or tub replacement: $7,000 – $15,000
- Full bathroom remodel: $14,000 – $28,000
- ADU bathroom build-out (including drain re-route if needed): $18,000 – $35,000
The biggest cost swing in Ontario comes from what’s under the slab. A lateral replacement or drain re-route adds $4,000 – $9,000. Homes built in the 1960s and 1970s with galvanized supply lines need a repipe add-on of $2,500 – $5,000. We give you a written line-item quote after the walkthrough, and the number on the quote is the number you pay. Call (855) 949-1913 for your free estimate.
We Also Serve Cities Near Ontario
While our focus is Bathroom Remodeling in Ontario, we regularly work in Montclair, Upland, Chino, and San Antonio Heights. Each of those cities has its own building department and its own quirks, but the material problems are similar: hard water, older drains, and homes built before modern waterproofing. If you’re just over the Ontario line, call (855) 949-1913 and we’ll tell you whether you need an Ontario permit or your own city’s.
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 – Bathroom Remodeling in Ontario
Many Ontario ADUs built in ZIPs 91761 and 91762 do need a lateral upgrade or re-route, because the original 1950s clay lines were sized for the main house only and cannot handle the added fixture load from a second bathroom. We pressure test the lateral before starting any ADU bathroom work, and if it fails, we replace or re-route it with 3-inch PVC. Call (855) 949-1913 and we’ll inspect your lateral as part of the free estimate.
In Ontario, we specify brushed nickel or matte black finishes with ceramic disc cartridges, solid brass drain assemblies, and porcelain or enameled cast-iron tubs rather than acrylic. Avoid builder-grade chrome, which pits and flakes within two years under Ontario’s water chemistry. We stock these fixtures locally and can have them on-site the week we start your Ontario project.
Standard shower pans work in most Ontario ADUs, but the subfloor and drain location have to be evaluated first. In the older detached ADUs off Euclid Avenue and Holt Boulevard, the original slab pitch often doesn’t match a pre-fab pan’s drain placement, so a custom mortar pan is sometimes the cleaner solution. We’ll tell you which one your floor needs during the walkthrough, not after demo.
Ontario’s hot inland summers and frequent 95 – 105°F days mean we spec higher-CFM exhaust fans and humidity-sensing switches in every ADU bathroom, plus a sealed waterproof membrane behind all shower walls. In a poorly ventilated Ontario ADU bathroom, condensation builds fast and feeds mold. We size the fan to the bathroom’s cubic footage and the desert climate, not a coastal spec.
Yes. Ontario enforces California’s current plumbing and electrical codes, and when adding a bathroom to a detached ADU, the city requires a separate plumbing plan showing the fixture count and drain line sizing. Our team handles the permit drawings and inspections for every Ontario ADU bathroom, so you don’t have to guess what the Ontario building department will flag. Call (855) 949-1913 with your address and we’ll tell you exactly what applies.
If you’re planning a bathroom remodel in an Ontario home or detached ADU, the smart first step is a walkthrough with someone who knows what’s under these slabs. Call Sunstone ADU Builders at (855) 949-1913 to schedule your free estimate. Nate Holloway will walk your property, pressure test your lines, and give you a written quote that covers the real scope, not a guess.
Written by Nate Holloway, Owner at Sunstone ADU Builders, serving Ontario, CA and the surrounding Inland Empire since day one.