Usually yes. Drains move by gravity, so the limits are slope, distance to the main drain, and venting. In a slab-on-grade Phoenix home, moving a toilet or shower means cutting concrete to reroute the drain, while a sink often moves with wall-run pipes. Moving any fixture needs a permit and inspection.
What decides how far a fixture can move?
Water supply lines are forgiving. They are pressurized, so they can bend around corners and run up, down and sideways. Drains are not forgiving. They work by gravity, so three things set the limit: slope, venting and distance.
Slope. A drain has to fall toward the sewer the whole way. The Phoenix Plumbing Code text says "Horizontal drainage piping shall be installed in uniform alignment at uniform slopes." The table in that section sets a minimum fall by pipe size: 1/4 inch per foot for pipes 2 1/2 inches or smaller, and 1/8 inch per foot for pipes from 3 to 6 inches. Every extra foot you move a toilet away from its current drain adds pipe that has to keep falling. That drop has to come from somewhere, and on a slab it comes out of the concrete. Our page on drain pipe slope covers the numbers in more detail.
Venting. A vent is the pipe that lets air into the drain so water moves freely and the trap seal stays put. The code says "Traps and trapped fixtures shall be vented in accordance with one of the venting methods specified in this chapter." That means a new spot needs a vent path, and the code also limits how far a trap can sit from its vent. Each fixture trap also needs "a protecting vent located so that the slope and the developed length in the fixture drain from the trap weir to the vent fitting are within the requirements" of a table in the vent chapter. We won't list that table here, because the numbers depend on pipe size and your inspector applies them to your exact layout. If you want the basics first, read what a plumbing vent is.
Distance to the stack or main drain. The farther a fixture sits from the drain it joins, the more slope you need, the more likely the vent gets awkward, and the more concrete or wall you open. A move of a foot or two is a very different job from moving a toilet to the other side of the house.
Which fixture is easier to move, and which is harder?
Every fixture has two sides: what it drains into and what feeds it. Supply is the easy side. The drain is where the cost and mess live. Use this table to size up your project.
| Fixture | What gets harder when it moves | On a slab foundation | On a raised floor or with an accessible crawlspace |
|---|---|---|---|
| Toilet | Largest drain of the four, needs steady slope and a vent, and needs clearance around the new flange spot | Usually means cutting concrete to reroute the drain | Drain can be rerouted in the floor cavity or from below |
| Sink | Small drain, but the trap must be vented and the trap-to-vent distance is limited | Often moves along the wall with new wall-run supply and drain | Easiest of the four |
| Shower | Drain must fall toward the trap, and the shower base has to be rebuilt at the new spot | Usually means cutting concrete for the drain and rebuilding the base | Doable, but the floor framing has to be modified |
| Tub | Heavy and large footprint, drain sits low, and it is often boxed into a fixed alcove | Usually means cutting concrete, and the drain location is fixed by the tub | Harder than a sink, easier than on a slab |
The pattern is simple. Small drains move easily. Big drains and low drains do not. A toilet and a shower both push a lot of water at once, and both sit at the floor level, so they have the least room to change.
### Why slab homes make it different
Many Phoenix homes are built on a concrete slab. On a slab, the drain lines run through or under the concrete. To move a toilet or shower, a plumber has to cut a trench in the slab, run new drain pipe at the right slope, tie it back into the existing drain, and then patch the concrete after the inspection. That is why the same toilet move is a bigger job on a slab than in a house with a crawlspace.
A sink is different. Sinks usually drain into the wall, not into the floor. If the new spot is on the same wall, or close to it, a plumber can often run new supply lines and a new drain through the wall and skip the concrete. That is the smartest place to gain layout freedom on a slab home.
Two more slab notes.
- Old pipe under the floor. If you are opening the concrete anyway, ask the plumber to look at what you find. Our pages on finding hidden leaks and on slab leak repair, reroute versus break explain why crews sometimes reroute lines through the attic or walls instead of breaking concrete. The same thinking applies to a fixture move.
- The toilet flange. If a toilet moves, the closet flange and its floor connection are new, not reused. Our page on fixing a broken toilet flange shows what that part does.
What do you need to check before you commit to a layout?
Before you lock in a plan, run through these checks. They save more money than any tile choice.
- 1Find the drain you will connect to. Ask where the nearest stack or branch drain is and how far the new spot sits from it.
- 2Check the clearances. The code text says a water closet, lavatory, urinal or bidet "shall not be set closer than 15 inches (381 mm) from its center to any side wall, partition, vanity or other obstruction." It also calls for a 21-inch clear space in front. If your new spot is tight, the toilet may not fit. See our toilet clearance code page.
- 3Check the venting. Ask the plumber how the fixture will be vented at the new location and how far the trap will sit from the vent. Ask whether an air admittance valve is even an option. Chapter 9 of the code has a section for them, but whether one is allowed on your job is up to the inspector.
- 4Check the floor and wall. A shower base, a tub or a wall-run drain needs framing space. A plumber should look inside the wall before you plan around it.
- 5Plan the trap. The code says "S" traps are prohibited, so a sink that moves to a new spot needs a compliant trap setup, not an old-style S trap.
- 6Confirm the permit path. More on that next.
Do you need a permit to move a fixture?
Yes, moving a toilet, sink, shower or tub in Phoenix takes a plumbing permit and an inspection. The City of Phoenix Planning & Development Department publishes a Work Exempt from Permit sheet, and it draws the line clearly. Swapping a toilet in the same place is exempt. Moving it is not. On the plumbing list, the exemption for reinstalling toilets holds only "provided such repairs do not involve or require the replacement or rearrangement of any valves, pipes or fixtures." The exemption for replacing toilets and fixtures carries this limit: "except that a permit shall be required for the relocation of any valves, pipes or fixtures." The sheet's own commentary puts it in one line: "Permit is not required for replacing a water closet, valve or fixture unless they or the connecting pipes are relocated."
So the rule of thumb is simple. Same spot, same pipes, no permit. A new spot, new pipes, permit and inspection. Exempt work still has to meet code, but a move never counts as exempt.
The inspection is not a formality. It is the point where someone checks slope, venting and joints before the trench is closed and the wall is covered. On a slab, that check happens before the concrete goes back. If you are planning a full remodel, read our page on whether you need a permit to remodel a bathroom in Phoenix, and our overview of what plumbing work needs a permit in Phoenix. For timing and fees, check with the city, since the exact fee schedule changes.
One caution. The exempt sheet on the city's site is dated, so confirm with the Planning & Development Department that it is still current before you rely on it. They can also tell you what applies to your address.
When is DIY fine, and when should you call a licensed plumber?
You can do the simple swaps yourself, but any move that changes a drain or vent belongs to a licensed plumber. DIY is reasonable when nothing moves. Swapping a faucet, a showerhead or a toilet in the same spot is a common homeowner job, and it is exempt from a permit. If you are replacing a toilet, EPA notes that "Design improvements have allowed toilets to use 1.28 gallons per flush or less while still providing equal or superior performance." So a like-for-like swap can also cut water use.
Call a licensed plumber when a move changes a drain or a vent. That includes any toilet, shower or tub move, any move that touches concrete, and any move that adds a fixture. A wrong slope or a missing vent does not show up on day one. It shows up as a slow drain, a gurgle or a sewer smell after the wall is closed. A licensed plumber can pull the permit and walk the inspection with you. Gas lines are a separate matter: they need a licensed pro and a permit too.
### What to ask a plumber before you approve a move
- 1Where will the new drain connect, and how far is that from the fixture?
- 2How will the fixture be vented at the new spot?
- 3Will we cut the slab, or can the drain run through a wall?
- 4What does the permit cover, and who handles the inspection?
- 5What does the price include, such as concrete patching and finish work?
- 6If you open the floor, will you check the pipe you find?
- 7Could a smaller move give me the same layout benefit?
Ask for the answers in writing, along with the price before work begins.
### The smartest way to plan a layout change
Here is the play. Keep the wet wall. Fixtures that stay on or near the same wall share the same drain and vent, so the layout changes without tearing up the floor. Move the sink and the vanity first, since they are the easiest to relocate. Leave the toilet and shower drain where they sit and change what is around them, such as the base, the glass and the finishes, unless the room truly does not work. If you must move a toilet or shower, do it once and do it during the same project as the tile and the flooring, so the trench and the patch are only done one time.
If you are converting a tub to a shower, our page on tub to shower conversion plumbing walks through what changes.
HQ Plumbing & Air is licensed and insured, offers free estimates and upfront pricing, and provides 24/7 service. If you are planning a move and want a straight answer on what your slab and your walls allow, we can look at the job and tell you what it involves before any work starts.