Weak water pressure (under load): Hack-job flip of single-family into 4 condos

SteamFTW

The building we've moved to is from 1900 (originally single-family), and in 2004 it was cut up into 4 condos, two first-floor, two second-floor. It has all the signs of having been a fly-by-night flip-and-run job, so I imagine every possible corner was cut. When we first moved in I thought the toilet supply line was clogged. You'd flush the toilet and it wouldn't fill at all--no, wait, there's a trickle! Eventually it would return to a proper fill-rate, I later realized that a neighbor's laundry had stopped filling at that same moment. None of the current tenants was around in 2004, but they have all said "it's been like that since we moved in," which for one poor person is going on 10 years.

Flow rate, pressure, pipe size, demand...I mean: these are all known relationships, right? My gut says the answer will be something like: our entire supply comes from some little pipe in a downstairs wall. I'm pretty sure the problem happens when any combination of condos draws water, not just between the two that are on the same side. So, where in the supply piping (from where it comes up of the ground in the basement) _should_ they have branched off to the individual condos? Might the supply pipe itself be too small? Or might there be a pressure-control valve in-line somewhere that was left at a single-home setting? Tell me what to measure and I'll post it.

Any suggestions for low-hanging fruit to check would be much appreciated.

Mad Dog_2

Start with the water service line entering the basement..front wall usually.  If it's not atleast 1" , that's a start.  For 4 apartments, I'd like to see a minimum of 1 1/4".  If its a 100 year old house, it very easily could be only 3/4" and I've seen old 5/8" lead service lines feeding a single family home.  

Take a few pictures 📷...it could be an old, wrought Iron or galvanized service that could have become greatly restricted over the years.  I would start there.  Mad Dog 🐕 

Intplm.

Is the water supply city water from a utility or is it from your own private well?

hot_rod

Liw street pressure
Undersized main line into building
Plugged or scaled pipe in the system
Valve partially open
Undersized PR
Plugged screen on PRV
Bad PRV

Measure static pressure, open a faucet, note pressure

Typical design will be a 7- 10 psi drop, full load, all fixtures flowing

IAMPO has a handy water calculator, WDC  for residential and multi family. It takes into account modern fixture flows

SteamFTW

All great suggestions. Thank you! @Mad Dog_2 I'll get some photos this weekend. @hot_rod Thanks for mentioning the IAMPO calculator.

jesmed1

Mad Dog_2 said:

Start with the water service line entering the basement..front wall usually.  If it's not atleast 1" , that's a start.  For 4 apartments, I'd like to see a minimum of 1 1/4".  If its a 100 year old house, it very easily could be only 3/4" and I've seen old 5/8" lead service lines feeding a single family home.

Just for reference, in our 100-yr-old 4-unit condo building, the water service line entering the basement is 1" (actual O.D.) copper. That size pipe carries throughout the basement, and then 1/2" lines branch off to different fixtures in the various units. We have 60 psi static pressure at the entrance, and no one here has complained about low water pressure that I know of.

hot_rod

Copper plumbing tube would be 1-1/8 OD if it is 1”

7/8” OD if it is 3/4

60 psi is plenty. It’s going to come down to how many fixtures run at once, and the gpm required

Tub fillers and hose bibs will be the big load 

jesmed1

hot_rod said:

Copper plumbing tube would be 1-1/8 OD if it is 1”

7/8” OD if it is 3/4

Ours is 1.050" actual OD, and it's probably brass, not copper, as it's turned black with oxidation. The closest nominal size I can find is for 1-1/16" (1.0625" OD) brass seamless tube. Odd size, but it's an old building.

Anyway, approx 1" OD service pipe at 60 psi is good enough for our 4 units.

EBEBRATT-Ed

Also a 1900 house likely had 1 bathroom , 1 kitchen and maybe no laundry.

Now with 4 condos you have at least 4 bathrooms, 4 kitchen and I am guessing 4 laundry hook ups and maybe 4 dishwashers.

JUGHNE

If the plumbing was a hack job, then piping was probably not flushed out.

I would check the sink/lab faucet strainers. Also the WC fill valves could be partially plugged.

Are the tub fill spouts just as slow as anything else? The tub filler usually has no strainer and would pass debris thru.

The strainers are probably not the main problem but at least one should start with them.

SteamFTW

@jesmed1 Thank you very much for a point of comparison and for the description of the tarnished pipe. Here's what I've discovered...

I found the service entry in a storage room, private to one of the condos. [pit-close-up.jpg] The line coming out of the stone foundation is OD (actual) 7/8". Not sure what material, but at best (when new and clean) ID would be about 3/4", right? It looks like what @jesmed1 described, just smaller. [Now see supply.jpg] That diameter (7/8" OD actual) remains the same through the old shut-off valve, meter, and to the vertical run, the vertical ball valve, tee with PEX and up to the bushing. The PEX line feeds the sill cock for the building.

At the bushing [supply.jpg] begins 1-1/4" copper (1-3/8" OD actual), but instead of going straight up to the tee directly overhead that splits the supply in two directions around the basement ceiling, it turns left for 6 feet to another shut-off valve and then back to resume a straight run into the ceiling tee. [loop-just-to-shut-off.jpg] and [loop.jpg]. This big loop seems to have been put in specifically to get a shut-off valve OUTSIDE the private storage area. The "common" space in the basement is on the other side of the chicken wire, behind the brewery stickers. I think you can see the yellow handle of the "common" area ball valve.

FWIW this is the only 1-1/4" copper (from the bushing [supply.jpg] and to the ceiling [loop.jpg]). The tee a reducing tee, so the "horns" are smaller than 1-1/4", and one side immediately goes into a reducer down to 3/4". The other side a few feet further on and after some twists and turns, I believe, drops to 1/2" before it leaves this area to supply the individual condos. When I have time, I'll trace everything correctly; it's a copper nightmare up there.

The other owners are away for the weekend. When they get back, I can have them incrementally turn on faucets, tub fillers, etc. while I record the pressure drop at the sill cock. Or maybe I'll do it at a washing machine, so that the gauge is not on that branch that only feeds the sill cock.

EBEBRATT-Ed

7/8" od means it is 3/4" copper nominal (plumbing size)

SteamFTW

@JUGHNE Good suggestions. I should have mentioned that. I checked them as a matter of course, as I do any time we've moved. Didn't see any debris--surprisingly--but also didn't see any evidence of someone having cleaned them out or replaced them prior to our arrival. It was after I had disassembled the WC filler and confirmed it was free and clean, that I thought maybe it was someone else in the building using the water at the same time.

bburd

Most likely the service line is both undersized for so many residential units and clogged with mineral deposits due to age.

Usually the customer is responsible for the service line from the curb cock / tap off the main to the meter.

jesmed1

bburd said:

Most likely the service line is both undersized for so many residential units and clogged with mineral deposits due to age.

And you'll probably find that a number of the 1/2" lines tee off to too many fixtures.

JUGHNE

The old original water service supply valve could be only partially opened.
If it is a globe valve is could have a fair amount of pressure drop.

Same for the water meter, it might be actually only 5/8" ID, another pinch point.

Jamie Hall

You say you aren't sure what material that service line is? If it's galvanized steel -- which wouldn't surprise me give the age -- it is likely to be almost completely rusted shut...

Mad Dog_2

As I said above, 3/4" (if that's what you have) is adequate for an average home with one 3 piece bath, KS, Hose bibb, maybe a slop sink.  Any additional domestic water load is pushing it. For many years, the water authorities installed 3/4" service lines to an average home.  In the last 20, all I see is 1"   Mad Dog 🐕 

mattmia2

I can't tell for sure because the part I need to see is out of focus, but it looks like a copper service with a copper adapter soldered on to it in to possibly a reducer in to that gate valve. The part that goes to the meter might be 5/8" pipe size, at least here that is common for single family residential and that meter and unions clearly hasn't been changed in decades.

@jesmed1 your service sounds like probably galvanized steel or iron but you would have to scrape some oxidation off to see what color it is underneath and see what fittings are on it. Sometimes they used brass but steel, iron, and lead were far more common.

Mad Dog_2

Right on Mattmia...The Water Company Gooseneck and meters were often 5/8".  It is very crusty and hard to tell, but I'm going with 3/4" K Copper as my Final Answer. There's a Flare nut on there.  There's a reason the plumber blew up to 1 1/4" ?? out of the meter outlet...He knew better or there was a volume problem right away.  Who knows...maybe he TOLD the G.C. or HO this might be the case, but THEY didn't wanna pay for a new, larger service and meter set.  

Enough Dickering around...Get a few prices on a new K Copper water service to the building.  1 1/4" Minimum, but I'd really rather see 1 1/2". Make sure they give you the appropriate size meter set and that the corporation cock on the street main is appropriately sized.  They are usually allowed to be one size smaller than the service line it supplies here in NY.  Good luck....Mad Dog 🐕 

jesmed1

mattmia2 said:

@jesmed1 your service sounds like probably galvanized steel or iron but you would have to scrape some oxidation off to see what color it is underneath and see what fittings are on it. Sometimes they used brass but steel, iron, and lead were far more common.

I scraped some of the black off and ours is definitely shiny brass underneath, turned black from 100 years of faithful service.

Mad Dog_2

Brass or copper? I've never seen a Flare Nut like that style for Brass Pipe.  It would connect with an IPS fitting, but that doesn't mean they aren't out there. If it is Brass pipe OR copper, interior mineral deposits shouldn't be the issue.  Measure the circumference with a string and then measure it with a Rule.  Then get a chart in internet that will convert that to either the O.D. of 3/4 or 1" Brass...if those numbers don't jibe, its likely K  copper tubing.  Mad Dog 🐕 

jesmed1

Mad Dog_2 said:

Brass or copper? I've never seen a Flare Nut like that style for Brass Pipe.  It would connect with an IPS fitting, but that doesn't mean they aren't out there. If it is Brass pipe OR copper, interior mineral deposits shouldn't be the issue.

For comparison, this is our 100-yr old service entrance. The elbow and nut between the shutoff valve and the meter are brass. To me, they look quite similar to the OP's service entrance of approximately the same vintage.

Our town just relined the water mains out in the street, and as part of that work they dug up and replaced the service lines running from the mains to each house. The old stuff they dug up looked to me like 3/4" or 1" copper. (This is in the Boston suburbs.) I was hoping to grab a piece of it, but the guy who was digging it up cut it in short sections and told me he was going to sell it for scrap. The pipe they replaced it with was plastic.

PC7060

@Mad Dog_2 - why copper for incoming supply, regional requirement?

In Virginia, incoming supply for single family is typically 1” Polyethylene Pipe (PE). 

In my old house I’m stuck with 3/4” PVC installed sometime in the last 20 years.  No idea why they didn’t go with 1”. 

Mad Dog_2

Ugh..plastic for water service?  They do allow it in some areas, but The Water Districts on Long Island 🏝 and DEP in NYC are sticking with copper.  Mad Dog 🐕 

PC7060

Mad Dog_2 said:

Ugh..plastic for water service?  They do allow it in some areas, but The Water Districts on Long Island 🏝 and DEP in NYC are sticking with copper.  Mad Dog 🐕 

Do you have trouble with corrosion of the service lines?

Mad Dog_2

Jesmed...There isn't any exposed service line that I can even see there between the Grounding clamp and valve.  They really played it close.  I always like a little meat 🍖 on the incoming line in case you have to reconnect down the line.  Im still betting HIS (OP) service line is Copper tubing..  Mad Dog 🐕 

jesmed1

Mad Dog_2 said:

Ugh..plastic for water service?  They do allow it in some areas, but The Water Districts on Long Island 🏝 and DEP in NYC are sticking with copper.  Mad Dog 🐕 

Yup, it's the way of the future. All the replacement natural gas piping going into the streets here is plastic too.

The way they relined our old cast iron mains was quite interesting. First they dragged a wire brush head through to get the old crap out. Then they inserted a hose that pumped cement through a spinning spray head. They dragged the spray head backwards as it rotated and sprayed cement on the pipe inside. The spray head was followed by an inverted cone that smoothed the cement onto the pipe wall. I saw a piece of relined pipe they later dug out. The cement coating was perfectly smooth, about 1/8" thick. It's a neat process. The contractor was Dewcon out of NJ. They go all over doing this water main relining.

hot_rod

There may be a strainer screen in that meter, another easy thing to check

SteamFTW

@mattmia2 I plan to take more photos when I can get better access to it. Zoom on my phone is hit or miss.

@hot_rod Hopefully that gate valve upstream still closes. 

jesmed1

Mad Dog_2 said:

Jesmed...There isn't any exposed service line that I can even see there between the Grounding clamp and valve.  They really played it close.  I always like a little meat 🍖 on the incoming line in case you have to reconnect down the line.  Im still betting HIS (OP) service line is Copper tubing..  Mad Dog 🐕 

Agreed his incoming is likely copper. Ours is too, I believe, at the connection just before the shutoff valve. Then it transitions to brass. The service lines the water contractors just dug up and replaced on our street were all copper.

Mad Dog_2

I can understand the yellow Poly Pipe.  We're seeing that all over NYS for mains and services Its one use of plastic I Agree with (Radiant & Snowmelt as well).  Its very thick walled and plastic welded).  I'm just not sure of the effects of plastic water bottles and plastic for domestic water.  We won't really for 50 yrs.  Mad Dog 🐕 

SteamFTW

Mad Dog_2 said:

There's a reason the plumber blew up to 1 1/4" ?? out of the meter outlet...He knew better or there was a volume problem right away.  Who knows...maybe he TOLD the G.C. or HO this might be the case, but THEY didn't wanna pay for a new, larger service and meter set.  

Yeah, that 1-1/4" run (before I found that it wasn't that big all the way back to the source) is what made me think to post this here. How could we have such a big problem if there's 1-1/4"? The little drinking straw upstream at the source--that's how.

My current theory is that the owner balked at the cost of a new larger service but was convinced to go with downstream pipe of the size that would be acceptable, when future owners are sick of the problem that was left them. I think that 1-1/4" run initally went from the bushing straight up to the ceiling tee. Then, after the condos were occupied, the owner of the condo to which that storage area belongs got annoyed with having to be home to let people in whenever the water needed to be turned off. The next plumber—maybe the same person as before—spliced in the big loop of 1-1/4" in order to put a shut-off valve in a place where anyone could get to it. One of the many things not solved by that solution is that the two sides of the basement were walled off completely from each other. Need to shut off the water to work on the West side? Not so fast: we still have to coordinate with one of the 2 condos on the East side first to get access to the "common" space shut-off valve, and to make sure both of them can do without water. Need to work on something water-related on the East side? Sorry, West side, your water gets shut off too. Actually, now that think about it, I don't think I've seen any valves that would isolate one condo from the rest. You probably have to shut off EVERYBODY's water anytime a single condo needs work. [HH needs to add the "facepalm" emoji.]

I can't believe all of this (ahem) less-than-ideal work is due to cost. The four boilers were brutally "spliced" into the original one-pipe system with a ridiculous amount of copper, which of course is wrong in the first place. Got my work cut out there! (Coming soon to a "Strictly Steam" near you). And the number of big cast brass/bronze fittings that were used to connect the new copper (!!!!) mains to the old sections--literally took my breath away. Money can't have been an issue--well, unless the heating work blew the budget.

Mad Dog_2

Or the materials "disappeared" off a jobsite.  When you see odd commercial grade fittings, valves and fixtures and ridiculously expensive items that don't belong, that is usually the case...Mad Dog 🐕 

hot_rod

What  is the incoming pressure? High pressure can make up for some undersizing

The limiting factor will then be flow velocity. 8 fps is the CDA recommendation. Intermittent flow to 10-12

A 5/8 meter can flow around 11 gpm at the high end

11 gpm in 3/4 K copper would be 8.1 fps velocity 

Low flow faucets and shower heads can help lower max demand

SteamFTW

@hot_rod I'll let you know in a couple days. Water is off while we have the sewer stack (just in the basement, fortunately) replaced and the old house trap removed. I can play when they're gone.

Intplm.

@SteamFTW your pictures look like a galvanized pipe coming in from the street. Either one-inch or three-quarter-inch diameter. That's inside diameter or (I.D.). the most important dimension in this discussion, as measured in the plumbing business.
Where the water flows is of course how the water goes. So the problems that you are having are most likely caused by the galvanized pipe that has built up with rust on the inside diameter as thoroughly mentioned above. This reduces the the volume of water lowering its ability to deliver your water as needed.
As your "gut" tells you from your first post you have a little pipe. Your pipe is coming into the building masquerading
as something larger.
This is a picture of a galvanized pipe I recently removed from a water main.
Note the beginning one inch ID. Rust over the years has accumulated on the inside diameter to about the size of a pencil diameter.

Larry Weingarten

Hi @SteamFTW , I don't know if it's been brought up, but why not take a magnet and test all accessible pipes? It's a certain way to know if there is any steel piping, which will clog up over time as @Intplm. has shown.

Yours, Larry

Mad Dog_2

My guess stands, thats a K copper tubing  service, not brass or Galvanized or wrought steel Pipe.  I'm sure they may have been made or used at some point,  somewhere 🤔 but any 
Piped in water service I have seen whether it's Brass or Galvanized or Wrought Iron connects to an I.P.S. Male or female adapter in to the first shut off valve or Water Meter assembly. That clearly looks like the brass flare nuts that we still use on underground services.  I guess we'll soon know.  Mad Dog 🐕 

mattmia2

Mad Dog_2 said:

My guess stands, thats a K copper tubing  service, not brass or Galvanized or wrought steel Pipe.  I'm sure they may have been made or used at some point,  somewhere 🤔 but any 
Piped in water service I have seen whether it's Brass or Galvanized or Wrought Iron connects to an I.P.S. Male or female adapter in to the first shut off valve or Water Meter assembly. That clearly looks like the brass flare nuts that we still use on underground services.  I guess we'll soon know.  Mad Dog 🐕 

You think that is a very square version of a short flare nut?

Edit: Oh, i see it now. The thing I thought looked like pipe is the back of the flare nut.

Mad Dog_2

Yup...mad Dog 🐕