Remodel folder · 5 sheets
Remodel Plumbing in the Right Order
Remodel plumbing follows the same inspections as new construction, rough-in before the walls close and a final once fixtures work, but it starts with demolition and whatever the old house hides.
Set by the Trench to Trim desk from code, agency and maker documents · how pages are made · Updated
Proof marks
- Under the 2021 IRC, replacing or rearranging pipe in a remodel takes a permit; the short exempt list covers fixing leaks, unclogging and pulling and resetting a toilet when nothing is swapped (ICC).
- Both the 2021 IPC and the 2024 UPC set a rough-in inspection before wall coverings and a final after fixtures are connected.
- A shower liner or pan is flood tested at 2 inches of water for at least 15 minutes under the model codes (2021 IPC and IRC, 2024 UPC) before tile goes on.
- Pipe, solder and flux that are not lead free have been barred from drinking-water plumbing since June 1986 (EPA).
- Paid crews disturbing paint in homes built before 1978 follow EPA's RRP rule, which always covers demolition of painted surfaces.
How does remodel plumbing differ from new construction?
Remodel plumbing works inside a finished house, so it begins with demolition and has to tie new pipe into old drains, vents and supply lines. The inspections are the same ones a new build gets: the 2021 IPC section 108.2 sets rough-in before wall or ceiling membranes and a final when fixtures are in place and connected.
What changes is the surprises. Opened walls can show rotted framing, undersized drains, old galvanized or lead pipe, or work done without a permit, and each one has to be dealt with before the new walls go up. Under the 2024 UPC, work covered before inspection must be uncovered when the inspector orders it.
What order do the trades work in?
Demolition comes first, then framing changes, then plumbing and electrical rough-in, the rough inspections, insulation and wallboard, waterproofing, tile and finishes, and the plumbing trim and final last. New Jersey's construction code puts the framing inspection after the rough electrical and plumbing inspections and insulation after every other rough inspection; tile, trim and fixtures follow drywall as normal trade practice.
Plan on at least two plumbing visits: rough-in while the walls are open, and trim after the finishes. The trim-out stage covers that second visit and the final.
Can you move a toilet or shower drain?
Usually yes, provided the new run keeps falling toward the stack and its trap stays close enough to a vent. A fall of 1/4 inch for every foot of pipe satisfies all three model codes (2021 IPC and IRC, 2024 UPC). On a slab the floor is cut and the new pipe is inspected before backfill; on wood framing the run goes through or under the joists.
A curbless shower adds a lowered floor or a raised room, a linear or center drain, and waterproofing across the floor. Schluter's installation handbook notes that recessing a floor may need a qualified design professional.
What do older houses add to a remodel?
Older houses add lead questions: lead service lines and lead solder in homes plumbed before 1986, and lead paint in homes built before 1978. EPA says lead pipes are more likely in older cities and in homes built before 1986.
EPA's coin-and-magnet check helps sort pipe types, and only a certified lab test confirms lead in water. Paid crews opening painted walls in a pre-1978 house need RRP certification.
Before any wall opens
- New or moved drains, vents, supply lines and any gas piping are a licensed plumber's work (a gas fitter where your state licenses one), under a permit.
- If you smell gas during demolition, get everyone out now; don't flip switches, use phones, light anything or start a car inside. Once outside and away, call 911 or the gas utility.
- Cutting joists or a slab is a structural change; ask whether an engineer or design professional must review it.
- Paid work disturbing paint in a pre-1978 home needs an RRP-certified firm.
- Your building department and a licensed plumber have the final word.
Which remodel jobs need a permit?
Most remodel plumbing needs one. Model-code exemptions stop at small repairs, and each city writes its own list on top; Bend, Oregon lets you swap an exposed sink, toilet or faucet without one but requires a permit to alter piping inside a wall or floor, add a fixture, or replace a shower pan.
Some cities let owners pull their own plumbing permit for a home they live in; rules vary by state and city, and the same inspections apply.
Remodel plumbing in numbers
- 180 daysLongest pause between inspections before a 2021 IRC permit lapses (R105.5)ICC
- 2 in. for 15 minWater depth and hold time for a liner test under IPC 312.9 (2021)ICC
- June 1986Start of the federal lead-free rule for drinking-water plumbingEPA
- 1978Cutoff year for houses covered by EPA's RRP rule when work is paidEPA
| Page | Main question | Key number | Who decides |
|---|---|---|---|
| Bathroom remodel order | What comes first | Flood test: 2 in., 15 min | Inspector |
| Kitchen remodel plumbing | Sink, island, dishwasher, gas | Dishwasher hose 33 in. high on one Bosch model | Plumber, maker, inspector |
| Moving a toilet or shower drain | How far a drain can go | 2-inch trap within 8 ft of its vent (2021 IPC) | Plumber, inspector |
| Curbless shower | Floor, drain, waterproofing | 1/4 in. per ft slope (Schluter, LATICRETE) | Plumber, design professional |
| Lead pipes in older homes | What to check before work | Lead free since June 1986 | Water system, certified lab |
Pressman's note
This hub summarizes the five remodel pages, drawing on the 2021 IPC and IRC, the 2024 UPC, New Jersey's construction code, the City of Bend's permit list, Schluter's handbook, Bosch's dishwasher instructions and EPA's lead pages, read October 2026. Prices, day counts and how-to steps for pipe or gas were left out on purpose.
Questions from the job site
Should plumbing be updated during a cosmetic remodel?
If walls or floors are opening anyway, it is the easiest time to look at old drains and supply lines. Replacing concealed pipe counts as new work under the 2021 IRC, so it brings a permit and inspection.
Who coordinates the plumber and the other trades?
On most jobs with one, the general contractor; the 2021 IPC puts inspection scheduling on whoever holds the permit. If you hire trades yourself, ask who that is.
Can a remodel pass inspection with old pipe left in place?
That depends on your building department. The inspector reviews what was changed and where it connects; ask what they expect for untouched pipe before the walls close.
What should be photographed before drywall in a remodel?
Every open wall and floor with a tape measure in the frame, the signed inspection card, and any old pipe you find, so later work can find what is hidden.
Does a remodel need the same tests as a new house?
New drain and vent work is tested under the model codes, and shower liners are flood tested. The inspector decides what portion of an existing system is included.
Where does the remodel order start for a kitchen and bath at once?
Both follow the same inspection points, so they are often roughed in together and inspected on the same visit, depending on how your contractor schedules them.
Stage pages
