Title: Shower waterproofing responsibility | Cercha
Description: Assign shower waterproofing, drain connections, water testing, and the release to tile. Record inspection status and the leak-response contact.
Canonical: https://cercha.pages.dev/guides/who-owns-the-shower/
# Who owns the shower: tile, plumbing, and waterproofing
Trade relationships
Name one builder contact and assign each shower interface in writing. Identify the membrane installer, drain connection, water-test lead, and release for tile.
You are scheduling a tiled shower, and plumbing and tile proposals both leave waterproofing partly “by others.” Close that gap before approving either scope. Name the membrane installer, drain-interface owner, water-test lead, and builder contact who releases the assembly for tile. Raleigh’s [residential inspection guidance](https://raleighnc.gov/permits/services/residential-inspections) includes shower-pan testing in plumbing rough-in.
Write down who completes each connection and who runs the test. Schedule the test before tile covers the work.
## Select the shower system before assigning the work
Begin with the selected shower detail. Identify the substrate, slope or base, drain, waterproofing product, corners, curb or threshold, and wall transitions. Have the proposed installer identify the components that keep water out of the framing.
Different systems use different details. [Oatey’s pan-liner guide](https://www.oatey.com/resources/project-guides/how-install-shower-pan-liner) describes a conventional liner installation with its drain and mortar-bed relationships. [Schluter’s water-test instructions](https://www.schluter.com/schluter-us/en_US/faq/shower-system-water-test-how-to) address its bonded-membrane shower system.
The [Oatey PVC liner product page](https://www.oatey.com/products/P_038753416311/oatey-pvc-shower-pan-liner) identifies that product as a concealed waterproofing liner. Confirm the selected product before assigning its installation. Get an approved detail before combining one system’s drain with another system’s membrane procedure.
For a liquid-applied example, [Custom Building Products’ RedGard data sheet](https://www.custombuildingproducts.com/TDS/TDS-104.pdf) sets substrate, application, drying, and testing requirements for that product. Red color alone does not show that the assembly meets RedGard’s instructions.
Ask the installer to submit the applicable documents before pricing is final. Record manufacturer guidance for unusual conditions, substitutions, or transitions.
## Assign the drain, membrane, test, and later work
Have the builder list the assignments from all proposed scopes on one worksheet. Use this table to plan the work; it does not decide legal liability.
| Work item | Assignment to make | Release evidence |
| --- | --- | --- |
| Framing and backing | Named framing or preparation crew | Accepted substrate condition |
| Drain and waste piping | Responsible plumbing contractor | Location, connection, required inspection |
| Base and slope preparation | Named installer | Selected system detail and acceptance |
| Membrane and transitions | Named waterproofing installer | Progress photos and product record |
| Membrane-to-drain interface | Named installer with plumbing coordination | Completed connection before concealment |
| Water test | Named test lead | Procedure, times, result, inspection record |
| Tile installation | Tile contractor | Authorization to cover accepted assembly |
| Glass and accessories | Named installers | Approved attachment and sealing details |
| Owner complaint intake | Builder’s named contact | Coordinated investigation and repair record |
Replace “named installer” with a company and responsible person. If a row has no assigned crew, hold that part of the award or work release until it does.
Include the worksheet in the [trade scope of work](/guides/trade-scope-of-work/). Ask both the [plumbing lead](/trades/plumbing/) and [tile lead](/trades/tile/) to acknowledge the same version. Separate material warranty terms from each contractor’s workmanship obligations.
## Name who sets up and witnesses the test
Specify who supplies the test equipment, prepares the drain, fills the assembly, records the starting condition, and attends the inspection. Name who monitors the test and who may drain the water afterward.
For KERDI, Schluter recommends waiting at least 24 hours after membrane installation before water testing under normal curing conditions. It recommends waiting longer in colder conditions. Its procedure describes a plugged waste line, marked water level, and an observation period. [Schluter water-test guidance](https://www.schluter.com/schluter-us/en_US/faq/shower-system-water-test-how-to).
Keep the waiting period separate from the test duration. Ask the installer to identify both from the selected system’s instructions and local requirements. Do not copy the KERDI waiting period to every liquid-applied membrane or conventional liner.
For RedGard, use the [current product data sheet](https://www.custombuildingproducts.com/TDS/TDS-104.pdf) to establish the applicable drying and flood-test conditions. Have the installer explain the procedure before setting a test appointment.
## Make the test record useful
Use a test sheet with these fields:
- Shower identifier and project location in the private record.
- System, membrane, drain, and applicable document revisions.
- Installer and test lead.
- Membrane completion time and recorded site conditions.
- Test preparation and starting time.
- Starting reference and observed ending condition.
- Inspection status, exceptions, and required corrections.
- Repair and retest record when needed.
- Person authorizing concealment.
Ask the tester to distinguish a leaking test setup from a suspected assembly leak. Record observations before choosing a repair. Ask the responsible installer and manufacturer to investigate an unexplained drop in water level before deciding what leaked.
Take photographs that show the setup and identify the shower. Retain them with the signed result. Ask the local official what must remain visible and which evidence it accepts.
The [shower-pan inspection guide](/guides/shower-pan-inspection/) helps coordinate the permit checkpoint. Raleigh also includes shower-pan testing within its plumbing rough-in guidance. [Residential inspections](https://raleighnc.gov/permits/services/residential-inspections).
## Protect the accepted assembly through later work
Give the tile crew a written release with any conditions. Tell the tile crew what it may cover, which items remain open, and whom to contact before modifying the membrane. Put unresolved work on the schedule and mark the location.
Before glass, benches, grab bars, or other accessories arrive, ask how their attachments relate to the selected waterproofing detail. Obtain approval of any penetration before drilling. Assign the sealing and recheck tasks to named parties.
Use the [trade-handoff guide](/guides/trade-handoffs/) to record later changes. Put this rule in the project instructions: report damage or a proposed change before covering it. Preserve the earlier test record and add the subsequent work record.
For the glass handoff, request the approved attachment layout and identify who verifies backing. For plumbing trim, confirm the selected fitting instructions and membrane interface. Check the instructions for the products installed on this job.
## Give the owner one complaint contact
Have the builder receive leak reports and arrange the initial investigation. Do not send the owner between tile and plumbing contractors while the scope remains disputed.
Collect the report, affected location, use conditions, photographs, and construction records. Arrange for the affected trades to inspect their connections under one plan. Establish any immediate protection measures, access authorization, and the person documenting findings.
Separate repair coordination from final liability decisions. Contracts, observed conditions, manufacturer requirements, insurance, and applicable law can affect responsibility. Refer unresolved responsibility questions to the appropriate professionals.
For North Carolina plumbing work, [G.S. 87-21](https://www.ncleg.gov/EnactedLegislation/Statutes/HTML/BySection/Chapter_87/GS_87-21.html) defines regulated plumbing contracting and licensing requirements, subject to exceptions. Confirm the plumbing scope with the responsible licensed contractor. Assigning waterproofing does not authorize an installer to perform separate regulated work.
Before closing a repair, retain the revised detail, work photographs, applicable retest or inspection result, and owner communication. State who completed each task and what follow-up remains.
## Give the tile lead a written release
Write a short notice identifying the shower, completed checks, required inspection status, and any open items. State who may authorize covering. Give the tile lead the notice before materials arrive so staging is not mistaken for permission to start.
If another crew changes a tested interface, describe the change and ask the responsible installer which checks must be repeated. Keep that answer with the revised release. The record should show what changed after the test and how that change was checked.
## Where Cercha fits
Cercha lets builders review tile and plumbing portfolios and builder or sub endorsements before starting a conversation. Use Messages to ask about the selected shower system and experience working across the drain and membrane interface. Establish the scope, testing responsibility, and leak-response process directly with the project team.
Published 2026.10.14. Updated 2026.10.14.
[More guides: Trade relationships]()
## Related guides
- [Shower pan inspection and water test]()
- [Writing a trade scope a sub can price]()
- [Trade handoffs: who accepts the work before the next crew]()
## Build your connections
[Ask about the beta]()
## Sources
1. Schluter Systems. (n.d.). *What is a water test? How do I perform one on the Schluter-Shower System?* Retrieved October 14, 2026, from https://www.schluter.com/schluter-us/en_US/faq/shower-system-water-test-how-to
2. Oatey. (n.d.). *How to Install a Shower Pan Liner*. Retrieved October 14, 2026, from https://www.oatey.com/resources/project-guides/how-install-shower-pan-liner
3. Custom Building Products. (2023, March 22). *RedGard Waterproofing and Crack Prevention Membrane / TDS-104*. https://www.custombuildingproducts.com/TDS/TDS-104.pdf
4. City of Raleigh. (n.d.). *Residential Inspections*. Retrieved October 14, 2026, from https://raleighnc.gov/permits/services/residential-inspections
5. N.C. Gen. Stat. § 87-21. https://www.ncleg.gov/EnactedLegislation/Statutes/HTML/BySection/Chapter_87/GS_87-21.html
6. Oatey. (n.d.). *Oatey PVC Shower Pan Liner*. Retrieved October 14, 2026, from https://www.oatey.com/products/P_038753416311/oatey-pvc-shower-pan-liner