Low water pressure

[lindsayA]

A little bit of history first. Our house was built in 1920. We live in southern Illinois. We have a 3 bedroom/1 bathroom house we are remodeling. The water pressure in the kitchen sink has decreased within the last year. The shower pressure has never been great. We have tried multiple sinks and shower heads with no luck. The house had metal pipes and my husband had been replacing as he went with pvc. Since he had the day off yesterday he replaced all of the metal pipes in our basement with pvc thinking that would solve the water pressure problem. No such luck. I have no knowledge of plumbing and he doesn’t have a ton but he doesn’t want to hire somebody. I can take more pictures if you let me know what you need. Thanks for any advice or troubleshooting you can provide!

 

[Tuttles Revenge]

It looks like the diameter of your water main is reduced right at the meter! Water volume and conversely water pressure is affected by the diameter of the piping throughout your plumbing system from the meter to each outlet.

Water piping should be "Sized" to match the total load of the house. Each fixture has a water usage rating. And the distance that the water piping travels is calculated into the sizing. So the total load and the furthest distance of fixture of the house is how we calculate the main water pipe size.

Some reading here for Illinois plumbing code for water piping.

Subpart I Water Supply and Distribution: Water Supply and Distribution, South Holland Plumbing Code | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Sizing starts here

Subpart I Water Supply and Distribution: Water Supply and Distribution, South Holland Plumbing Code | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

 

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[lindsayA]

It looks like the diameter of your water main is reduced right at the meter! Water volume and conversely water pressure is affected by the diameter of the piping throughout your plumbing system from the meter to each outlet.

Water piping should be "Sized" to match the total load of the house. Each fixture has a water usage rating. And the distance that the water piping travels is calculated into the sizing. So the total load and the furthest distance of fixture of the house is how we calculate the main water pipe size.

Some reading here for Illinois plumbing code for water piping.

Subpart I Water Supply and Distribution: Water Supply and Distribution, South Holland Plumbing Code | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

Sizing starts here

Subpart I Water Supply and Distribution: Water Supply and Distribution, South Holland Plumbing Code | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

That makes sense to me but my husband isn’t getting it. He says since the bathroom sink has pressure it must be something else. Is it because the sink uses less water than the shower?

 

[WorthFlorida]

Tuttle is correct. Right after the meter it's reduced to 1/2". It should be 3/4" to the heating system and water heater. Then branch off to a fixture or bathroom group with 1/2" for the best flow rate. The outlet from the water heater should also be 3/4". The correct CPVC is used.

Right after the water meter a spigot can be added. It will allow to get a water flow measurement from the city water and the house plumbing can be drained when shutting off the water before the meter.

The cement seems to be clear in color. Oakley does make an all purpose cement in milky clear for PVC, ABS and CPVC. CPVC cement only is yellow or orange. Do check the cement used.

 

[Tuttles Revenge]

That makes sense to me but my husband isn’t getting it. He says since the bathroom sink has pressure it must be something else. Is it because the sink uses less water than the shower?

OK. So what is likely happening is that a section of pipe or fixtures in an area are clogged with debris. This causes low water volume and the perception that the water pressure is low in an area. Are there still old galvanized / metal pipe in those areas? Like in the wall where they are less accessible to be changed? Sometimes a chunk of rust can travel down the pipe and get stuck inside the angle stop valve, the supply tube or in the faucet itself, and eventually small particles getting clogged in the aerator screen.

In a faucet you can start by taking off the aerator and testing the flow rate. if that isn't improved, then taking off the supply tube from the faucet and running water into a bucket... then if that isn't improved taking off the stop valve at the wall and running water through a hose to the outside (clamp the hose onto the outlet to avoid a massive spillage)

 

[WorthFlorida]

........ Is it because the sink uses less water than the shower?..........

Depending on the age of the fixture. Showers heads have a max EPA rating at 2.5 gallons per minute at 60 PSI. Most replacement heads are far less to meet many local code restrictions and to get the EPA Water Sense rating, 1.2 to1.5 gallons per minute.

Old bathroom faucets are about the same. Old ones were at 2.5 or more gallons per minute. I have a home built in 2007, all CPVC with plenty of pressure but all the new Delta faucets used for the bath remodeling are rated a 1.2 gallons. The pipe to the faucet is only 1/4".

How is the flow from the bathtub faucet when filling the tub?

 

[LLigetfa]

He says since the bathroom sink has pressure it must be something else. Is it because the sink uses less water than the shower?

Yes, volume has a lot to do with friction loss. Water speeds up travelling through smaller pipe and the distance and volume both conspire to rob pressure through friction loss.

 

[Reach4]

Get a garden hose thread pressure gauge. That will let you quantize what you are dealing with. You can hook that to a hose spigot, a laundry tap, or the drain valve of the water heater.

When you are not using water, note the pressure. Then not the gauge reading when you run the shower.

Water Source™ 100# Presssure Test Gauge With 3/4" Female Hose Swivel

The Water Source™ 100# Pressure Test Gauge checks the water pressure in a plumbing system. It reads from 0 to 100 PSI and has a swivel fitting to fit a 3/4" male hose bibb or garden hose.

www.menards.com

But yes, most lavatories have less flow than a showerhead.