CPVC undersized?

[Dale Young]

I called this CPVC piping out due to weak hot water flow in kitchen, Master whirlpool, shower, and sink. The PVC cold water flow was excellent. The pipe shown was also not secured for the clothes washing machine. The pipe stated 1/2 CPVC, this must be the exterior diameter because the PVC was also 1/2 was defintely larger their for maybe interior diameter. Am i on the right track and should the CPVC be plumbed with different larger pipe? The remodling contracted stated "this is standard size pipe and is very much adequate for the dwelling". If thats the case why is the flow significantly weaker than cold water? SECOND ISSUE: Whirlpool tub's hot water faucet made a LOUD Roar when turned on by itself. The remodling contractor stated " will adjust stem to eliminate noise. Could this also be the result of the small CPVC piping? Thanks for any help!

[James H. Bushart]

Originally Posted by dyoung

I called this CPVC piping out due to weak hot water flow in kitchen, Master whirlpool, shower, and sink. The PVC cold water flow was excellent. The pipe shown was also not secured for the clothes washing machine. The pipe stated 1/2 CPVC, this must be the exterior diameter because the PVC was also 1/2 was defintely larger their for maybe interior diameter. Am i on the right track and should the CPVC be plumbed with different larger pipe? The remodling contracted stated "this is standard size pipe and is very much adequate for the dwelling". If thats the case why is the flow significantly weaker than cold water? SECOND ISSUE: Whirlpool tub's hot water faucet made a LOUD Roar when turned on by itself. The remodling contractor stated " will adjust stem to eliminate noise. Could this also be the result of the small CPVC piping? Thanks for any help!

Is there a contractor disputing your findings? If so, I hope you are not responding to him and -- particularly -- I hope you are not modifying your report.

Both would be disadvantageous and will paint you into a corner.

With that being said, I would not remark as to any possible cause for weak water flow. I would call it out and recommend that the contractor fix it. Since you did provide a possible cause and he apparently disagrees with your description of it, it does not change the fact of the weak water flow that he needs to repair.

[William Warner]

Schedule 40 PVC is typically not approved for water distribution within the home... at least not in my area.
Your second photo shows schedule 40 PVC... not CPVC
Check what is approved in your area, but it may be incorrect altogether.
1/2" diameter may be inadequate sizing depending on lengths and fixtures and the calculations should be performed by a competent plumber (not the home inspector). If you have CPVC to PVC connections, the may also be unapproved depending on your AHJ.
Weak flow, PVC, etc, should be called out for further review and repairs as necessary...

[Jeffrey R. Pope]

1/2 inch CPVC is usually acceptable for individual fixture-supply lines. It may simply be the fixtures. Perhaps they are "low-flow" or "ultra low-flow" type fixtures. That being said, you haven't posted any pictures of CPVC.

I don't know of any jurisdiction that allows PVC for interior distribution.

[Dale Duffy]

I don't know of any jurisdiction that allows PVC for interior distribution.

Nor do I.......

[Robert J. OConnor]

Originally Posted by jpope

I don't know of any jurisdiction that allows PVC for interior distribution.

Nor do I ... but (there is always a but) ... What was the static water pressure?

[Dale Young]

Have to check static water pressure? Jeff, in the first photo, the pipe i'm holding is CPVC and in the second pic under the kitchen sink, the pipe on left of two vertical is CPVC. As far as low flow, the contractor did say the shower head was low flow; but the cold water side was much stronger than hot water? As far as single run lines, One single line to master bath and one single line to kitchen (sink, dishwasher) and a branched off to washing maching?

[Jeffrey R. Pope]

If you say so, but it all looks like PVC in your pictures. 1/2" pipe is the minimum size allowed for "branch" piping (some fixture types require larger), but should not be used to supply multiple fixtures.

It really comes down to delivery rate. Check with your local AHJ, but generally 3 GPM is considered "acceptable" for individual fixture supplies, but many low-flow fixtures will reduce that to a maximum discharge of 1.5 GPM.

[Michael Larson]

Originally Posted by jpope

If you say so, but it all looks like PVC in your pictures. 1/2" pipe is the minimum size allowed for "branch" piping (some fixture types require larger), but should not be used to supply multiple fixtures.

It really comes down to delivery rate. Check with your local AHJ, but generally 3 GPM is considered "acceptable" for individual fixture supplies, but many low-flow fixtures will reduce that to a maximum discharge of 1.5 GPM.

In fact photo 2 clearly shows PVC marked on the side of the pipe.

Never suitable for hot water supply and only allowed for cold in some jurisdictions.

[Robert J. OConnor]

I'm not aware of any "low-flow" fixtures that would result in a noticeable difference in flow between the hot and cold lines at the same fixture.

About the pipe sizes keep in mind that CPVC tubing and PVC pipe follow different standards. The IRC specifies that CPVC tubing for water distribution pipe follow CTS dimensions per ASTM D2846 (e.g. 0.625" OD and 0.485" ID for 1/2" CPVC ... same OD as copper tubing), while PVC pipe follow IPS dimensions per ASTM D1785 (e.g. 0.840" OD & 0.622" ID for 1/2" Sch-40). But the IRC does not list PVC as acceptable for either cold or hot water distribution piping (your local mileage may vary). See this site for more info on plastic pipe/tubing ... http://www.ppfahome.org/products.html

Normally 3/4" tubing for the main lines and 1/2" tubing for the distribution lines usually results in adequate flow for the average 3-4 BR 2 bath house ... Unless there are other issues ... one of which is low pressure. Especially since you indicated good flow with the larger PVC cold water lines, and weak flow with the smaller CPVC hot water lines. Which is why I asked what the static pressure is.

And it looks like some galvanized steel piping in Pic #2 ... is that abandoned or possibly gas piping? If still part of the hot water distribution that might also result in lower water flow for those lines (known history of problems with internal corrosion, clogs, and leaks).

If I see low flow at fixtures I typically would check static water pressure to help me decide what to check more closely and how to report the findings ... but most SOP's don't require checking pressure. In any event note the issues and let the contractor figure out what the causes are and how to correct them.

JMO & 2-Nickels ...

[Dale Young]

The contractor is trying to get out of the fact there is a problem; and stating that the plumbing co. did the work correctly and does want to fix it. I am standing firm on my findings and hope between the realtors and my client she gets it corrected. My client is retired and moving to my area on a fixed income and doesnt need to fix it. I just hope everybody else does their part. Thanks everyone! NACHI is the best!

[William Warner]

Are there building codes in your area?
Most around here require permits and inspections of work for repairs greater than a 3 foot section. Your photos and story indicate a complete re-plumb of this house.
Having them show proof of the proper documentation and approvals to the sellers would be a simple solution.