Hey everybody. So I'm wondering if anybody out there can help me? I need to replace my water pipes which are galvanized. I am replacing them at the main shut off valve coming from the city. By the way, I live in Chicago,IL. I have to run them to the water boilers. Then from there One boiler is going to feed the second floor and the other one is for the first floor and the basement. There is a full bathroom in the basement. I don't know what size to use or how to run the risers. If anyone can give me some info on the correct way to do this I would appreciate it.

If you want to be technical about it that you should take in consideration developed length of pipe, incoming pressure, and peak demand. Then you look up size of your new pipes in Pipe Sizing Tables.

You are not saying whether you have washing machine and those 2 bathrooms have tubs only, showers only or tub/shower combos.

But as a rule of thumb - and to stay on the safe side: 1" main line extended to the first bathroom and hot water heater. Then you can reduce to 3/4" line to feed the other bathroom and kitchen sink. Each plumbing fixtures can be fed with 1/2" pipes that "Tees-off" from the 3/4" and 1" pipes.

All hot water in 3/4" inch main run, 1/2" pipe to each fixture.

Undersizing your pluming through out your house will cause "noisy pipes" ( friction noise audible when water in use ) and "low volume delivery" ( ... many times confused with "low pressure" ).

Plumbing for exterior fixtures, like hose valves and sprinklers should Tee-off before pressure regulator. Pressure regulator should be installed if your incoming pressure exceeds about 75psi. We always run 1" pipe to sprinklers and 3/4" for hose valves. That way your sprinklers and hose have enough volume.

Hope that helps... Milo

If you want to be technical about it that you should take in consideration developed length of pipe, incoming pressure, and peak demand. Then you look up size of your new pipes in Pipe Sizing Tables.

You are not saying whether you have washing machine and those 2 bathrooms have tubs only, showers only or tub/shower combos.

But as a rule of thumb - and to stay on the safe side: 1" main line extended to the first bathroom and /or hot water heater. Then you can reduce to 3/4" line to feed the other bathroom and kitchen sink. Each plumbing fixtures can be fed with 1/2" pipes that "Teed-off" from the 3/4" and 1" pipes.

Undersizing your pluming through out your house will cause "noisy pipes" ( friction noise audible when water in use ) and "low volume delivery" ( ... many times confused with "low pressure" ).

Plumbing for exterior fixtures, like hose valves and sprinklers should Tee-off before pressure regulator. Pressure regulator should be installed if your incoming pressure exceeds about 75psi. We always run 1" pipe to sprinklers and 3/4" for hose valves.

Hope that helps....Milo

OK. There is a shower, toilet, and sink in the basement with washer and a utility sink. Also two lines for garden hoses.
On the first floor there is a bathroom with a toilet, sink, and tub and shower. A sink in the kitchen. On the second floor there a bathroom with toilet, sink, tub, and shower. One sink in kitchen.
The water heaters are in the basement. Now do I run a 1" line to the first floor and from water heater to first floor as well?