SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Quoted from "OakLawnMDB"

...Another meter and/or line sounds like a lot of extra $$. We live in a residential area, 55FT wide lot, sidewalks, curbs etc. and the current line comes up through the lower level concrete floor. It doesn't sound like a simple or cheap option...

A second water meter may or may not be cheap. If you get one, you would not have it coming to the house and deal with the concrete floor, you would instead have it located out in the yard near the street. The actual cost (to the water company) is pretty minimal. The initial cost might only be a couple hundred dollars. But I've also heard of places where the water company is having a hard time meeting watering demands. In places like that, they might charge $1,000 or more for a water meter because they are trying to discourage additional connections. But the primary issue with trying to justify a 2nd meter is the cost of sewer. Because the 2nd meter would only be used for outside watering, you would pay zero sewer rates for the 2nd meter. That can be a huge savings if you have really high sewer rates. The other thing to factor in is whether there is a minimum monthly charge for the 2nd water meter.

As a personal example, when I looked into a 2nd meter for my house, the initial cost was only about $300. The minimum monthly fee was about $10 (and that pays for something like the 1st 1,000 gallons or something). When I looked at expected water usage and savings in sewer fees, I determined that the system would pay for itself in about 10 years (and would have been a lot sooner if there wasn't the $10 minimum for the winter months when it wouldn't be getting used at all).

Now one thing strikes me as odd from your description. It SOUNDS like this is a relatively new subdivision and that you live in an area where winters are not particularly harsh. If I'm right, it sounds odd that your water meter would be inside the house. I wouldn't think IL is so cold that the meter needs to be indoors to protect it from freezing, and being inside a house seems like more work for the water company when it comes time to read meters. So at the risk of sounding insulting... are you sure thing "thing" in the house is a water meter and not a pressure regulator?

It would be worth following up on Boot's idea of the water company having a regulator installed before the meter. You should be able to contact your water company and ask them what sort of water pressure is expected in your neighborhood, it there a water company installed regulator, if so, can it be adjusted, and if not, can installing a 2nd meter allow you to get more pressure? It's worth at least asking.

A separate meter will not increase your pressure. You have to figure on losing at least 15 psi through the RPZ and zone valves and sprinkler pipe and fittings. Reduce your design flow, and the losses in the house plumbing will also be reduced. You can do a 1400 sq ft front lawn with 5 gpm, so just plan for running two rotors in a zone. No question that Maxipaw heads will spray further than any gear drive at low pressures, but if you must have gear-drive rotors, you can make Hunter PGPs work in a low pressure design, by using more heads spaced closer together.

Quoted from "Wet_Boots"

A separate meter will not increase your pressure.

Sorry if I created any confusion that a 2nd meter could increase pressure.

That could only be the case if, as Wet Boots suggested, there was a city owned regulator before the existing meter. Then I could see a 2nd meter getting installed with either no regulator, or a regulator set to a higher level. Other wise, the ONLY reason to consider a 2nd meter would be if you could get significant savings on sewer rates.

I don't have any experience with Maxipaw or Hunter PGPs, so I can't speak to their operation. But I'm using http://www.mprotator.com and been quite pleased with them. They have various models and all work on only 25psi. The MP2000 will throw 17 feet @ 25psi using only 0.6 gpm for a 180 degree arc (1.2 gpm for a 360 arc). Stretched, that would be enough to water the entire yard on a signal circuit. Divide the yard up into two or three circuits, and the project is sounding doable.

But we've already covered ways to reduce some of those pressure losses.

If you follow Boots' suggestion of designing for a 5GPM system, Jess' instructions indicate the psi pressure loss of the meter drops to 1psi. That will also drop ALL of the flow dependant pressure losses (such as losses in the mainline).

At 5GPM, if you use 1" Sch40 PVC pipe, the pressure losses in the lateral lines will be about 1 psi. (The calculator at Jess' site indicates 100' of 1" Sch40 @ 5gpm only has a loss of 0.66psi.)

So if you redo the design for 5gpm and use 1" pipe:

01psi - Water Meter
11psi - Backflow
01psi - Mainline
02psi - valves
01psi - laterals
25psi - sprinmkler heads
=====
42psi - total loss

That still give you a little breathing room for the valves (which Jess says you should assume 5psi if you don't have specs for the valves you plan to use).