An underground water service is being installed between the meter and the building. Which of these materials is approved for use as water service pipe?
- AABS plastic pipe of the type used for building drainage
ABS is a drainage material. It has no pressure rating for water service and no potable water listing, and it will fail under continuous service pressure.
- Cross-linked polyethylene tubing rated and listed for potable water service
- CSchedule 40 PVC DWV pipe assembled with solvent-welded joints
PVC DWV pipe looks like pressure pipe and cements the same way, which is what makes it tempting. It carries no pressure rating and is not permitted for potable water; pressure-rated PVC is a different product with a different marking.
- DCopper DWV tubing assembled with soldered joints
Copper DWV tube is thin-wall drainage tube. Copper water service uses the heavier pressure types, not DWV weight.
Why B is correct
Cross-linked polyethylene tubing listed for potable water is among the materials the water service table accepts. It is manufactured to a pressure rating and to a potable water standard, which are the two qualifications that separate service pipe from drainage pipe.
What this question is testing
The item tests the candidate's ability to separate pressure and potable-rated water service materials from drainage materials that share the same base plastic or metal, using the material tables rather than appearance.
On the job
The failure mode here is a leftover stick of DWV pipe on the truck and a service that has to be finished before the concrete crew arrives. Read the printing on the pipe: pressure pipe is marked with a pressure rating and a potable water certification mark, drainage pipe is marked DWV. On plastic services also confirm the tracer wire or locating method your jurisdiction requires, because a buried plastic service that nobody can locate becomes somebody's excavator damage later.
Memory technique
Service pipe holds pressure and holds drinking water. DWV does neither.
Exam tip
If the option says DWV, it belongs to drainage. Water service options carry a pressure rating.
Where to look it up
Chapter 6, Section 605 and the water service pipe material table. Approved material lists differ between IPC and UPC, and several jurisdictions further restrict plastics underground, so verify against your adopted code.