Remodeling Your Bathroom or Kitchen? Don’t Forget the Plumbing

Oliver Owens
Dec 24, 2025
6 min read

You’ve picked tile, cabinets, and that gorgeous matte-black faucet. Love it. But here’s the truth every remodeler eventually learns: the best finish work falls flat if the plumbing behind it isn’t sized right, vented right, or installed right. Good plumbing is what makes the space feel effortless—hot water that doesn’t run out, drains that don’t gurgle, and fixtures that don’t drip a month after the reveal.

This guide walks Anaheim, Placentia, and nearby homeowners through the plumbing decisions that matter most during a bath or kitchen remodel—so you can enjoy the look and the daily comfort for years.

Why plumbing planning belongs at the top of your remodel checklist

Hidden choices affect everyday comfort. Pipe size, venting, and valve selection are invisible on day one but determine water pressure, temperature stability, and drain performance for decades.
Layout changes have code & cost implications. Moving a shower, island sink, or toilet isn’t just “shifting pipes.” It changes drain slope, trap arm distances, venting routes, and often permits/inspections.
Old piping + new fixtures = weak link. Brand-new faucets connected to 40-year-old galvanized or cast iron is a recipe for low flow, discolored water, and recurring clogs.
Doing it twice is expensive. Opening finished tile to fix a buried mistake costs way more than doing it right during rough-in.

Start with the big picture: What’s staying and what’s moving?

Before you fall in love with a layout on Pinterest, talk through the plumbing routes behind it.

Bathroom

Toilet moves are the biggest driver of cost because of the 3–4" drains and required slope. In slab homes, that often means trenching concrete.
Shower swaps (tub to walk-in) usually require a 2" drain and correct pan/liner or bonded waterproofing system—not just a pretty tile.
Dual vanities need adequate supply lines, an updated vent, and either a double fixture tee or properly spaced traps—not two drains jammed into one.

Kitchen

Island sinks need special venting (often an AAV or loop vent if a standard vent can’t be routed). Don’t let this become an afterthought.
Dishwasher + disposal require the right air gap or high loop and a compatible baffle tee—not whatever was in the parts bin.
Gas lines for ranges require correct sizing and shutoff access, and sometimes upsizing if you’re adding a second gas appliance (range + grill line, for example).

Pro tip: If you’re remodeling on a slab (common in SoCal), anything that affects buried drains should be finalized before demo. Once concrete is cut, changes get pricey fast.

Upgrade the backbone: when repiping during a remodel makes sense

Remodels are the best time to address older piping. If you have galvanized steel, aging copper with pinholes, or cast iron drains that have seen better days, consider a strategic repipe while walls are open. You’ll get stronger flow, fewer surprises, and cleaner water.

Supply lines: PEX or Type L copper are the usual winners. PEX shines for remodels—flexible, quieter, and resistant to SoCal’s mineral scale.
Drains: Updating brittle ABS sections or scaling cast iron prevents chronic clogs.
Shutoffs & stops: Replace crusty angle stops with quarter-turn valves at every fixture.
Pressure management: If pressure is 80+ psi, we’ll add/adjust a PRV so new fixtures are protected and warranties stay intact.

Curious if a partial or whole-home repipe is smart during your project? Book a quick Repiping consult and we’ll give you honest options.

Rough-in details that separate “fine” from “fantastic”

1) Supply sizing & temperature control

Shower valves: Choose a pressure-balancing or thermostatic valve so a toilet flush doesn’t ice your morning.
Water heater check: New body sprays or a soaking tub may require a larger tank, a mixing valve, or a tankless upgrade to keep up with demand.
Recirc options: If the run to your primary bath is long, consider a recirculation line or pump for near-instant hot water.

2) Drain slope, trap arms, and cleanouts

Slope matters: ¼" per foot on most horizontal drains keeps waste moving without leaving solids behind.
Trap arm limits: Every fixture has a max distance to the vent—ignore it and you’ll invite siphoning and smells.
Cleanouts: Ask for smartly placed cleanouts (toe-kick, cabinet, or exterior wall) so future maintenance doesn’t require demo.

3) Venting done right (especially islands & freestanding tubs)

Vents let air follow water so traps keep their seal. In kitchens with islands or baths with standalone tubs away from walls, plan the venting early. Sometimes an AAV (air admittance valve) is appropriate; sometimes code and long-term reliability favor a routed vent.

4) Waterproofing & transitions

Use a proper shower pan system (liner + pre-slope or bonded waterproof membrane).
Coordinate tile heights, niche locations, and valve trim depths—the rough-in depth has to match your final tile thickness to avoid proud or recessed trim.

5) Noise control

Secure lines with proper clamps and isolation to avoid water hammer and pipe chatter, especially behind thin vanity backs and island cabinets.

Fixture selection & installation: buy nice, install right

High-efficiency doesn’t have to mean finicky. Choose fixtures with reliable internals and parts you can get locally.

Toilets: Look for MaP-tested performance (1.28 gpf that actually clears), quality wax ring or wax-free seals, and a solid supply line—not the cheapest braided hose.
Faucets & shower trim: Stick with major brands for future cartridge availability. Verify trim matches the valve body model (mix-and-match causes headaches).
Kitchen sinks: Decide early on top-mount vs. undermount; undermounts need solid support and silicone seals done right the first time.
Garbage disposals: Size for your cooking habits and confirm compatibility with the chosen sink, dishwasher, and baffle tee routing.

Want stress-free install and warranty-safe hookups? Tap our Fixture Installation service and we’ll set, level, seal, and test everything—then document it for your project file.

Don’t skip permits and inspections

Anaheim and surrounding cities expect permits for most layout changes, drain relocations, and new gas runs. Permits protect you during resale and ensure venting, slope, and materials meet code. We coordinate with inspectors regularly—our goal is zero surprises at sign-off.

Remodel sequencing: how we keep your project on schedule

Pre-demo walk-through: Verify fixture locations, heights, and any trenching or slab cuts.
Rough-in: Install new drains, vents, and supplies; pressure test and cap.
Inspection: City sign-off before walls close.
Close-up & surfaces: Walls, waterproofing, tile, cabinets, tops.
Set & finish: Install fixtures, connect appliances, test flows/drains, label shutoffs.
Final QA: Photos, pressure/temperature readings, and homeowner walkthrough.

Accessibility and future-proofing while the walls are open

Blocking for grab bars in showers—even if you’re not installing them now.
Comfort-height toilets and single-lever faucets for easier use.
Shower benches and handheld sprayers on a slide bar.
Laundry box upgrades with metal quarter-turns and hammer arrestors.
Smart leak sensors at the water heater, sink bases, and fridge—to alert your phone before a drip becomes a disaster.

Common remodel pitfalls (and how we prevent them)

Pretty tile, poor pitch: We flood-test pans and verify linear drain elevations so water moves the right way.
Valves set too deep/shallow: We rough to the trim’s spec, factoring tile + thinset + membrane thickness—no guessing.
Undersized gas: Adding a pro-style range? We calculate demand and meter distance so flames stay steady.
Forgotten air gaps/high loops: We route dishwashers to code to avoid cross-contamination and smells.
Old shutoffs left in place: We replace with quarter-turns so a small repair doesn’t require a whole-house shutoff.

Budgeting smart: where to save, where to invest

Save on: Decorative extras that are easy to swap later (mirrors, hardware, basic faucets).
Invest in: Drain/vent layout, quality valves, shutoffs, a quiet disposal, and water heater capacity. Those are the parts you won’t want to open walls to change.

Quick checklists

Before demo

Finalize fixture models & rough-in specs
Confirm any toilet/shower moves (and slab trenching if needed)
Decide on repipe scope (partial vs. whole-home)
Schedule inspections & coordinate with GC

Rough-in day

Verify valve depths and niche heights
Confirm drain slope and vent routes
Pressure test supplies; cap and label lines
Photograph everything before close-up

Before the reveal

Set fixtures with new stops and braided supplies
Test every drain under load (fill, flush, and observe)
Check temperatures/pressure at all points
Review warranties, manuals, and maintenance tips

Ready to remodel without the plumbing regrets?

Bring us in early—even for a quick layout sanity check. We’ll flag the gotchas, size the piping, and coordinate with your GC so everything passes inspection the first time and performs the way it should.

Book Fixture Installation for a clean, warrantied set-and-seal of your new faucets, toilets, shower systems, and kitchen gear.
Schedule a Repiping consult if your remodel opens walls around older galvanized, pitted copper, or cast iron—this is the moment to upgrade.

You handle the style. We’ll handle the science behind the walls—so your new space feels as good as it looks, day after day.