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Kohler Home Additions & ADU: The San Jose Owner’s Guide
Kohler home additions and ADU construction in San Jose typically run $53,100 to $153,400 for a permitted addition, and $106,200 to $259,600 for a full ADU build. We install Kohler fixtures and plumbing systems as part of these projects, with written pricing confirmed before any work starts. Most homeowners call us after a failed attempt with another contractor left them with unpermitted work, a leaking rough-in, or a Kohler tub spout that was mounted to a wall with nothing solid behind it. If you’re holding a Kohler valve cartridge or fixture that failed mid-project or mid-shower, this page tells you what it costs to make it right, done by the book.
Key Takeaways:
- Kohler-compatible home additions in San Jose run $53,100 – $153,400; ADUs run $106,200 – $259,600
- Written price before work starts, every time. No numbers that move at the door.
- 365-Day Done Right Promise: if it fails within a year, we return and fix it at no charge.
- Bradford Remodeling Co San Jose is an independent contractor, not affiliated with Kohler.
- Call (669) 272-2637 for a free estimate. A live person answers.
Which Kohler Models This Applies To
We work across the Kohler fixture lines most common in San Jose additions and ADUs: Purist, Stillness, Anthem, and the older Devonshire and Bancroft series that show up in ranch homes around Willow Glen and Cambrian. The compatibility gotcha with Kohler is the valve body. A Purist trim kit will not mount to a Rite-Temp valve body from a Devonshire rough-in, even though both are “Kohler.” If you’re matching a failed valve to an existing wall, take a photo of the valve body behind the trim plate before you buy anything. The model number is stamped on the brass, not on the plastic escutcheon.
For Kohler showers and tubs, the two workhorses are the Rite-Temp pressure-balancing valve and the newer high-flow thermostatic mixing valve, which behaves differently at low water pressure and needs a different cartridge altogether. OEM versus aftermarket matters here: Kohler cartridges are made to a specification that generic knock-offs rarely meet, and a cheap cartridge in a Kohler body will whistle, dribble, or seize within a year in San Jose’s hard water. We install OEM Kohler parts by default. The cost difference is small. The callback cost is not.
Styles & brands we work with
Signs Your Kohler Home Additions & ADU Is Failing
- Water pressure drops to nothing when someone flushes a toilet. This is the Rite-Temp cartridge wearing out or the pressure-balancing spool sticking. It presents as a cold blast or a hot scald when another fixture draws water. Replace the cartridge, don’t flush the whole valve.
- The tub spout pulls off the wall in your hand. We see this constantly in San Jose additions. The rough-in was set too deep or too shallow, and the spout was never anchored to blocking inside the wall. A Kohler spout is a finish part, not a structural one. If it pulls, the substrate behind it failed.
- Brown staining at the base of a new Kohler toilet or tub. Hard water mineral buildup is one thing. Persistent staining in a new addition is usually a bad wax ring or a drain that was pitched wrong at rough-in. Neither is a fixture problem, but both live in the same room and look like one.
- Grout lines crack along the change of plane where a Kohler shower meets the pan. Movement at a wall-to-pan joint means the substrate or subfloor flexed, which means the waterproofing membrane almost certainly tore with it. Kohler shower pans don’t fail first; the prep does.
- You can hear water running inside a wall when nothing is on. That is a leak in a supply line or a failed solder joint, often at the valve body itself. It will not dry out on its own, and it will find the ceiling below it. Call before it finds it.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
For a Kohler fixture repair or replacement inside an existing addition or ADU in San Jose, you’re looking at $470 to $2,125 for a valve cartridge or tub spout swap, including the part and labor. A full bathroom rough-in during an addition runs $10,620 to $33,040 depending on whether we’re moving drain lines or tying into existing stacks. A complete kitchen including Kohler fixtures runs $16,520 to $53,100. Every number we give you is a written line-item price before a single tool comes out. That is The Garrison Standard, and it applies to every project we touch.
What drives the range: whether the wall has to come open to reach the valve, whether the substrate behind the tile is sound, whether your existing drain lines are cast iron or ABS, and whether the project is permitted. A Kohler cartridge swap on an accessible valve might take 90 minutes. A rough-in correction behind a finished tile wall can take three days. We will tell you which one you have in writing before we start.
Every Kohler part we install is covered by the 365-Day Done Right Promise. If the part or our workmanship fails inside a year, we return and correct it at no charge. That is the written guarantee, signed, in your hand at job close.
DIY or Call Us?
A homeowner with a Phillips head and patience can swap a Kohler shower head or an escutcheon plate. You can also check the supply stops behind the toilet. But the moment you are pulling a cartridge out of a Kohler valve body or opening drywall to get at a rough-in, you are past the point of safe DIY. If you cross-thread a Kohler valve body or crack a solder joint inside the wall, the repair just doubled. And if the work is in a rental ADU in San Jose, the city will want it permitted and inspected anyway.
We stock Kohler Rite-Temp cartridges, spouts, trim kits, and supply valves on the truck for the models we see most in San Jose additions: Purist, Stillness, and Devonshire. If we don’t have your oddball part on board, our parts runner pulls it from a local Kohler supplier, usually the same day. Call (669) 272-2637 and we’ll give you a straight answer on the phone, zero pressure.
FAQs
Expect 8 to 12 years from a Kohler Rite-Temp cartridge in San Jose’s water conditions, and closer to 15 from the valve body itself. Hard water shortens that. If your cartridge is 10 years old and acting up, replacement beats repair every time. Call (669) 272-2637 for a free estimate.
Cartridges and stops inside a Kohler valve can be rebuilt, yes. A cracked brass valve body cannot. We always try the cartridge first because it is the cheapest fix, but we will not rebuild a valve that is not worth saving. We’ll show you the old part before we install the new one.
A cartridge or tub spout swap takes 60 to 90 minutes. A full valve body replacement behind a finished wall takes one to two days including patching, and tile repair may add another day if the wall finish has to match. We will give you a written timeline before work starts.
We stock Rite-Temp cartridges, supply valves, tub spouts, and trim screws for the Kohler series we see most in San Jose: Purist, Stillness, Devonshire, and Bancroft. Specialty trim and colored finishes are ordered from a local Kohler distributor, typically same-day. Call (669) 272-2637 and we’ll check the truck while you’re on the line.
Straight number, written scope, done when we said done. That is how Curtis Lane runs every Bradford Remodeling Co San Jose job, whether it is a $470 cartridge swap or a full two-story addition. The Garrison Standard backs it in writing. Call (669) 272-2637 for your free estimate.
Written by Curtis Lane, Owner, Bradford Remodeling Co at Bradford Remodeling Co San Jose, serving San Jose and nearby areas.
