Diagnose & Fix Clogged Cold Water Pipes

Weak Cold Water Pressure, Hot Water OK

John, an InspectApedia reader, successfully diagnoses clogged cold water pipes. He traced the problem to a clog that principally blocked the cold water supply to the building after the first Tee downstream from a whole-house water filter.

On 2023-04-02 by john m - significant drop in cold water flow, hot water flow is fine

I am on a well with a whole house sediment filter. Recently, I started seeing a drop in flow only on the cold side. Running a single faucet is fine but opening another faucet or flushing a toilet causes a significant drop in flow.

I don't see the same problem on the hot side. The well pump seems OK, turn on-turn off are still at the proper pressure settings. Well reservoir tank pressure is set to 4 PSI below well pump turn on pressure.

My guess is that I have an obstruction somewhere in the cold water distribution. The house is plumbed with CPVC. Any advice on locating an obstruction? Any other possibilities?

On 2023-04-02 by InspectApedia Editor (mod) - follow the pipes from cold supply to first branch-off for hot

@john m,

Thanks for a cold water pressure drop question -well put.

As you say hot water pressure (flow rate) is not diminished but cold has weakened, that does sound as if there's an obstruction on the cold side of your water supply piping.

If the weaker cold water "pressure" is at all cold water using fixtures, then the blockage is probably ahead of the closest fixture to the main cold water line, but because you say hot water flow is unchanged, the blockage is also probably past the point at which incoming cold splits off to send some cold into your water heater.

Follow the cold water piping from the point at which it splits off a line into your water heater.

Look first for any shutoff valves or other devices that might be a clog point.

Even though it's not completely rational (as hot flows OK and cold not) I might see if by pulling the faucet strainer at fixtures closest to the cold supply we could, by running water full force for a few minutes, flush out some debris.

If not, then we're reduced to the more-troublesome sequence of a series of openings in the cold supply piping system, testing flow at each point to see where it runs full-pressure. (The blockage will be downstream from that point).

Luckily, it's really easy to cut-into and then re-connect CPVC piping using a couple of inexpensive tools and SharkBite fittings like the one I show below.

Do keep me posted. DF

On 2023-04-04 by John M - decided to check the ICEPURE CTO10BB water filter

@InspectApedia Editor

I was thinking about it and decided to take a look at the old filter. I noticed that there's usually an inner "cloth" lining on the output side. It was missing on the old filter so I wanted to at least look for that in the piping.

I got a couple shark bite connectors before cutting into the lines.

Unfortunately, a good portion of the lines are covered by sheetrock but cut into the main distribution line as close as I could.

I used a cheesy borescope to look down the pipe and lo and behold, I could see the piece of fabric right at the first T where the lines begin the distribution throughout the house.

Time to cut into the drywall and finish the job. Again, thanks for the help and don't buy ICEPURE CTO10BB filters!

On 2023-04-05 by John M - re-posted by (mod)

@InspectApedia Editor , (re-posting lost comment - DF)

Apologies John, somehow the Comment box system lost part of our conversation so I'm re-entering what I can recall of your follow-up comments about

Lost cold water pressure, hot water pressure un-changed:

John M said (*paraphrasing)

I decided to examine the whole house water filter. It consisted of a filter cartridge and a cloth cover.

I found that the water filter's cloth cover had torn and part of it was lost.

Following the cold water line from the pump to the first Tee where cold splits off to supply both house cold water and house hot water, I found that the plastic tee was quite blocked by the fabric shed by my filter.

[John: please tell us again the brand of water filter that gave this trouble, and please re-post photos so that we can show the larger, higher-res copies than what we have here - DF]

On 2023-04-04 by InspectApedia Editor (mod) - successful cold water flow ("pressure") diagnosis

@Anonymous,

Brilliant diagnosis - a filter shed material into the water piping.

Since you reported that only cold water flow rate was diminished, I suspect that the cloth filter material that was shed was clogging only the cold line.

Nice going. I'd sure appreciate seeing photos (one per comment) of the T and the clogging cloth when you or your plumber makes the repair.

On 2023-04-05 by john m - blockage found at tee in water piping

@InspectApedia Editor ,

I ended up having to replace the Tee. I tried to fish out the cloth and poke it through without success. Fortunately, Lowes is open late and I was able to get parts. The first picture is with the Tee cracked open a bit

On 2023-04-05 by john m - filter cloth elements came apart more than once, clogged pipes.

@InspectApedia Editor ,

Second picture is of the filter cloth elements. Looks like I had two filter failures. I'm surprised that I got any flow at all the way they were packed in so tightly. Again, I appreciate all the help!

On 2023-04-05 by InspectApedia Editor (mod)

@ John M

Thanks so much for taking the time to follow-up with photos of the water filter cover that was shed and that clogged at what we think is perhaps the first Tee in the water piping system downstream from the water filter.

The position of the clog must have blocked more of the continuing pipe to cold water supply than the continuing pipe (past the tee) to the hot water supply system, as you reported that cold flow was diminished but not hot.

Great detective work to check at that first Tee and to find the water filter shed-materials.

Apologies that we lost part of your comments and also the larger original version of your photos.

Because this diagnostic will certainly help other readers, particularly for cases such as the one you describe and where a particular brand of water filter or filter cartridge shed its cover, resulting in a pipe clog - I'd sure be grateful if you'd add any additional comments you recall such as the brand and model of the problem water filter and water filter cartridge, and if you could re-post the original larger version of your photos.

Also, let me know if you have success using SharkBite fittings for a quick, easy piping repair.

Thanks again - Daniel

On 2023-04-05 by InspectApedia Publisher (mod)

@John M - & for other readers, here is an image of the water filter discussed by John m.

We looked at the manufacturer's website and literature for an illustration of the cover that John described - without finding it.

But we certainly see remnants of a cover in John's photos.

Is it possible that when you installed the water filter, there was a filter "cover" that should have been removed and discarded, that is that was not intended to be included in the filter installation?

On 2023-04-05 by InspectApedia Publisher (mod)

@john m,

Thank you, this discussion will help other readers.

DF

On 2023-04-05 by john m

@InspectApedia Editor ,

The filter is an ICEPURE CTO10BB 1 micron Sediment/Activated Carbon 10" x 4.5" cartridge bought on Amazon. Photo attached

Also see WATER PIPE CLOG DIAGNOSIS
and
see CLOGGED SUPPLY PIPES, HOT WATER