Adding Pressure Tank and Pump to City Wa
I have a 70 year old house with a 3/4″ copper water supply line that is 350′ long. We are on the Detroit water system and have about 55 PSI of pressure with no flow. Of course with the 350′ of supply line, as soon as I draw water I get a significant pressure drop.
I am adding 2 bathrooms for a total of 3 full baths. I want to supplement the flow without digging up 350′ of front yard and paying the City $1500 for a 1-1/2″ tap to the main. I am considering 2 solutions:
1) Add a pressure booster such as found on www.pressurebooster.com. The concern I have with this is the pump will not be able to draw enough volume of water through the supply line and will cavitate.
2) Add a pressure tank in the house to upplliment the volume and add the pressure booster described above to give adequate pressure. I am a little concerned about the draw down in the tank. What would happen if the pump emptied the tank. The pump is supposed to shut down when the inlet water supply is insufficient. Also I wanted to put a low air pressure in the tank as I want volume not pressure. The pressure would come from the pump.
Do any of these options seem feasible? Are there any other cost effective and feasible solutions that I have not considered above?
Thanks for the help.
Tim
Replies
I think you know that your problem is more a lack of volume than pressure. Assuming the meter is at the street, I think you ought to consider replacing the 350' run with a 1" or 1.5" plastic line. The smaller diameter line from the main to the meter will be OK as long as it is not more than about 15'. Increasing you pressure much may cause other problems, and you still may not have the gallons per minute you desire. I may be wrong...
where I live I have ~14 GPM at the meter outlet, and ~5 GPM at the hose bib on the house. There is ~100' of 3/4" plastic from meter to the house and pex piping in the house. Also, a plumber told me that he hates pex because the fittings restrict water flow so much.
Edited 12/26/2004 11:37 am ET by DIRISHINME
I know I have a volume proplem. That is why I want to suppliment volume with a tank and then to give good pressure add a pressure booster. I think this would work without tearing up the entire yard and I would guess a replacement of the supply line would be in the $5000 or more range. A pump and tank about a 1/5th of that and still work fine.
Tim
I think that you can get by with just the tank. Get a large tank with a bladder fill the air bladder with about 45psi that will hold your pressure . and the incoming water will try too return to the 55psi that you have at static. If I am wrong then you can buy the pump.
From a systems point of view, a bladder tank will function as a capacitor, and will do wonders for you if you put in a good check valve as mentioned previously. It will allow you to collect extra water; then, when your demand exceeds what the city line will provide, you have that extra capacity in the tank to draw from.
You could take a leaf out of a method used widely in the UK. Incoming water is feed to the kitchen sink for drinking water. A spur is ran to a tank in the attic (fill level controled by ball cock valve) and feeds a heated storage tank for hot water. Cold water feed for the bathrooms comes from the tank in the attic. Run 3/4 +" pipe and tubs and sink fill quickly, showers need to be pumped or on the ground floor for pressure. Rain heads do work well with large pipe feeding them.
A few other details which are different, the dishwashers are feed from the cold water and heat their own.
I thought I was the only one with this problem.
In 1999 I bought land. I removed a mobile home and built a house. The water line was a private line attached to the municipal system, shared by 4 home owners. I was the first in line. The furthest down the line was perhaps 1000 feet away.
The line had been repaired over the years, with the result that the line from the main to the first house (me) was only 1".
If I was the only one using water I was fine. But, one day the next to the last home owner got fed up with frequent loss of pressure that he installed a well pump and pressure tank connected to the supply line. When his pump kicked on, the rest of us had really low pressure, and the guy at the end would suck air when he turned on the faucet. So he went out and bought a pump. That sucked the pressure from the second house, so he bought one too.
Frequently in the morning my water would stop completely. One morning in the shower it stopped after I was soaped up. I stood there waiting so long I air dried. All I could do was wipe the soap off with a towel and get dressed.
I considered a pump, but instead installed a bladder tank with a check valve to prevent back flow out of my house. When all was quiet in the line my tank would fill to full capacity at the maximum pressure the main reached overnight. Then, I could take a shower in the morning with good constant pressure. It worked fine and was an inexpensive and adequate solution. The only problem was that if I took a really long shower, once the tank was empty the flow dropped suddenly. It was not a gradual tapering off of pressure.
I think a pressure tank, without a pump, is worth a try for you. You could always add the pump later. Make sure the tank is big enough for all the people in your house, and that the check valve is a high quality one. Install an electrical line for a pump if it would be difficult to add after construction.
The ending to my story got better. After a year, the village installed a new main right in front of my house and installed a 3" tap for us at no charge. We were all happy after that.
I agree that a bladder tank with backflow preventor on the in line will help.
Increasing the pressure will do nothing to overcome the flow restrictions in the small long line, but increasing the diam of that line for any distance will help too.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
WayneL5
I know the feeling. My dad's house is 110 years old. The supply line is 3/4" in to the house and I'm sure the gavanized pipe is good for about 1/8" to 1/4" now. To make matters worse he has 3 floors. If you flushed a toilet on the 1st floor you got air on the 3rd floor. I don't want to live with that in my new house. I hate it when the soap dries on too!!
Tim
Basically, to do the best job (without digging up the pipe) you need a backflow valve, low pressure cutoff switch, pump, and tank. You could probably get by if you had just the backflow valve and tank, if you had a large enough tank, but you'd get by with a smaller tank with the pump.
You need both the backflow valve and cutoff switch for legal/safety reasons: It's considered naughty to let water flow backwards out of your house into the muni system, and it's also naughty to draw a vacuum on the incoming line (since that can cause nasties to be sucked in through any small leak). (Also, the cutoff switch helps prevent pump damage from running dry.)
The system on the page you referenced seems to have all that, but the pressure tank is awfully small, since it expects to have a continuous source of water and only does the low-pressure shutdown as a safety measure.
I wonder if, rather than putting the pressure tank ahead of the pump to assure a continuous flow, you should put the tank after the pump, with a valve in-between to allow you to limit flow to what the 3/4" pipe can deliver.
I don't think its necessary to spend the money for a backflow preventer; a simple check valve will suffice.
The backflow preventer would prevent the flow of water back into the municipal system in the event it lost pressure. It has additional safety features that makes it more effective than a check valve, including a two stage unit with drainage between. But that's not what you are encountering. The municipal system is pressurized all the time. If it lost pressure then every thing connected to the system all over town would face the same situation and your one preventer would not help. If protection were needed for that then everyone in town would already be required to have one.
In your case all you are trying to do is prevent loss of pressure in the bladder tank, which a simple check valve would do.
A backflow preventer/check valve is often required by the water company, and is "being a good neighbor" even if not. Reduces the chance of some mishap in your plumbing causing problems for someone else. The valve in this case need not (unless otherwise required by local authorities) incorporate an air bleed -- you just want to keep water from flowing backwards.
I'm trying to remember the "technical term" for a backflow preventer... do you (or anyone else) know it?
Matt
A "backflow preventer" is generally, two check valves in one package, with air release/vacuum breakers installed.
If I understand the original problem, there is a peak/demand capacity problem, caused by the long 350 ft run of small pipe. The original problem was the reluctance to replace the 350 ft line, due to the expense. Therefore, the obvious work-around is a pressure tank with a check valve (or backflow preventor if you want to spend the 500 bucks), to give you that extra peak/surge capacity.
Adding a pump wont help the real problem, as it will probably cavitate due to the restricted suction line.
RPZ - that was the term I was looking for. Light came on... eventually. Then I had to go look it up to see what it stood for: Reduced Pressure Zone. Matt
I have a flyer from FEBCO and they list 6 types of backflow preventorsReduced Pressure (RP)
Double Check (DC)
Pressure Vacuum Breaker (PVB)
Atmospheric Vacuum Breaker (AVB)
Dual Check (DUC)
Dual Check with Atmospheric Port (DCAP)Looking at there chart a reduced pressure unit will work.But a double check or dual check will also work as you don't have toxic checmical on the other side.And from Febco's offering it appears that dual check and douvble check are probably more commonly available in "home sizes" (3/4-1"), but RP are also available in those sizes.
"...a replacement of the supply line would be in the $5000 or more range. A pump and tank about a 1/5th of that and still work fine."
if you're handy enough to install it yourself it shouldn't cost more than about $350-$500, depending on the size of your pressure tank and pump. i did it a couple years ago- it's no big deal so long as you're familiar with basic plumbing and electrical work. (1/2hp flotec pump w/ 42 gal equivalent tank) you'll probably need to put the pump on its own breaker, too.
also, don't waste your $ on the cheap $3-$4 brass hinged 'flapper' type check valves- they leak. get the expensive, $8-$12(!) kind with the rubber seat and a spring.
m
My intent was to let the pump draw from the pressure tank. That way I would get good pressure in the house and the tank would always refill from the city line. If the tank is big enough then It will never empty. This depends on my peak demand which I figured would be 3 showers for 20 minuts at 2.5 g/m or 90 gallons. I would assume the tank would refill as soon as the pump draws water extending the time I can take a shower!!
From all the responses, any combination of what was proposed would be acceptable. It just depends on how effective it turns out to be and whether or not a Pump is required.
Thanks for all the help.
Tim
I'd consider option #2. This gets done all the time in the local towns where people are right at the high point of the line or at the end somewhere. Small (!) pump - don't need more than 2-5 gpm, 30-40 gallon pressure tank, and check valve or balckflow preventer, depending on what the municipality requires. You may already have a check valve on the line if you have a water meter.
On new residential jobs around here, I always ask the town if I can use plastic (HDPE). If so, we specify 1-1/4" to the house unless it's over 500 feet, then we go to 1-1/2. If the answer is no, we spec 1" 'K' copper. I think 3/4" supply line is totally inadequate for a residential supply. On my own well system, I asked for 1-1/4" supply line, even though the well driller told me he always used 1". No thanks.
The simplest, most uncomplicated solution would be a roof-top or attic tank, if the building's structure can support that kind of weight.
Ideally, you have a tank that will contain twice your estimated needs for the re-fill time, and this tank is filled by either a low-capacity pump or your muny water supply. If the tank is large enough, the refill does not have to be fast; thus the volume problem you have will cease to be a problem.
The additional benefit of having the tank above all your taps is excellent pressure.
In New York City, muny water pressure is only sufficient to deliver a usable volume of water to about the 5th or 6th floor of a building; that's why you see so many wooden roof-top water tanks there. It's a good system.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
That would be a good simple solution. Unfortunately my house is a story and a half with a planned master bedroom suite on the second floor. The upstairs shower, sink, toilet and bath would be above the level of the tank. Thanks for the suggestion though.
Tim
So put the tank in the basement. Get one of those west-Texas water heaters (roughly 50 gallon black plastic tank with a float fill valve) and put it in the basement, then run your pump off of that.
You could always build a water tower in the back yard. Neighbors'd really love that!
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?