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Crashless 07-09-2008 04:07 PM

Water Main Replacement Advice
I'm thinking about having the water main for my 1926 house replaced and I had a few questions.

A majority of the plumbing is galvanized piping, the water main is currently 3/4" galvanized - 12 years old minimum (previous owners said they hadn't replaced it) We're having fairly major pressure problems in our 1 story house where we can't run more than one fixture at the same time.

We recently replaced and moved our tanked water heater with a tankless, and when our water was turned back on a LARGE amount of debris came out of the system. The water immediately came out brown and took about 10 minutes at each fixture to become clear again. We had to remove the screens in all our faucets to clear them out. Basically a big pain.

Our plumber recommended replacing the water main first and going from there. The city recently (about 2 years ago) replaced the main down the middle of the street and it enters our water meter as 1" copper. The meter steps it down to 3/4" which runs to our house.

The plumber also recommended a 1" copper main. He said he could step it up from the house side of the meter and run it to the house. This seemed counter intuitive to me. Is there anything to be gained by using 1" copper when the meter steps it down to 3/4"?

Should I also have the city come out and replace the meter with one that is 1" all the way through?

Any info would be greatly appreciated. My first instinct is that 1" copper is simply more expensive than 3/4" and he is up-selling me. Am I crazy?

Thanks in advance.

Marlin 07-09-2008 04:29 PM

Galvanized hasn't been used for water supply lines in many years. Your main is probably closer to fifty years old. It could possibly be the original main. Galvanized as you have discovered has a tendency to rust inside restricting flow and spewing debris. If you have galvanized pipes inside as well replacing the main may not fully solve your problems. You may have to replace the galvanized lines entirely to have ample flow.

One thing I would recommend before you go replacing pipes is to do a pressure test on your water lines. Make sure you have 40psi or better. That will tell you for sure you have a flow problem and not a pressure problem.

As for 3/4" vs. 1" Despite the increase in price he will probably make the same thing off the job either way. He probably has nothing to gain by selling you the larger size. How many bathrooms, half baths, kitchens, hose bibs, washing machines, etc do you have? Do you plan on adding any in the future? That will determine what size main you need.

On to the meter... Are you sure the meter is actually reducing it or are there fittings on the meter reducing the pipe size which could be removed? If you have a 3/4 meter then you would have to get a larger meter from the water company to get the full benefit of the 1" pipe.

Crashless 07-09-2008 04:37 PM

Thanks for the quick reply.

I have tested the pressure in the past to work on my irrigation system and it was definitely above 40psi. As for fixtures we have:

1 full bath
1 kitchen
1 clothes washer
4 hose bibs (I assume a bib is a garden hose connection?)
and a full irrigation system

We have plans to add an additional bathroom at some time.

I'll take a close look at the meter tonight, but as I remember it the galvanized pipe screws directly into the meter and there does not appear to be any extra fitting attached. Typing this out now, that does seem odd...I'll take a closer look.

Marlin 07-09-2008 05:01 PM

You could probably get by with 3/4 if it weren't for the irrigation. I'd go with the 1". It's an expensive job and a couple hundred bucks now may prevent years of lousy pressure and/or eventually replacing the line.

Crashless 07-09-2008 05:06 PM

Sounds great!

I'll call the city to see about the water main tomorrow. Is that something that should be free, or do they charge for stuff like that?

Is there an order that is preferable when changing both? IE: Main then meter or vice versa?

Thanks again.

mstplumber 07-10-2008 09:02 AM

You are probably OK with the meter you have. A 3/4" meter will flow plenty of water. The reason for installing a larger main is to minimize pressure drop due to friction loss in the pipe, Smaller pipe creates more of a pressure drop per linear foot, so even though the meter will give you enough flow, the pipe starts slowing the water down as soon as it leaves the meter. I have a 5/8" meter and a 600' long water service. I used 1 1/4" and have great flow for both my house and an irrigation system. Your pressure has a direct bearing on this, of course.

As far as the galvanized is concerned, Marlin is absolutely right. You will probably wind up having to replace all of the galvanized piping in the entire system to really correct the problem. If you cut out a piece of you 3/4" galvanized you will probably find a channel about the size of a pencil for the water to get through. Once you replace the service, the problem might get worse because the increased flow pressure to the rest of the piping often dislodges more accumulated rust which can lodge in the diminished passages, especially in elbows, tees and valves.

Crashless 07-10-2008 11:45 AM

Yeah, I have a feeling that replacing the main will only expose MORE problems...but I think to start I'm just going to replace the main with the 1" line (thanks for clarifying the 3/4 meter question). Then my wife wants to redo the laundry room to move the machines.

After that, the only old piping that is left will be the bathroom and the kitchen. With a little luck, it'll hold out a couple more months to spread out the cost a little. We've gotten a quote to replace everything and it's not _too_ bad, so we know we have to do it anyways - just need to come up with a plan.

Thank you all so much for the help.

majakdragon 07-10-2008 12:46 PM

Call your water service provider before making any plans. I worked for a major City water department for a few years and there are costs involved with installing larger meters. Most house meters are called 5/8" meters. The piping from them is 3/4". Going to a larger meter may also have an initial cost for the larger meter and also a monthly charge. You may want to think about a seperate meter for the irrigation system. This is especially true if your water bills are based on water and sewer. Just a thought.

wilderbeast 08-11-2009 06:15 AM

Hi There, I'm a plumber from New Zealand, just curious, but to me 1" copper sounds like an expensive option. Do you guys not use MDPE (plastic) water pipes over there. All new water mains over here have gone the way of plastic...:huh:

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