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PEX in Chicago: a gamble worth taking?

alamont | Posted in Building Code Questions on

I’ve recently begun the renovation of a frame construction two-flat in Chicago. Its two separate apartments with a basement and an unfinished attic. I have researched PEX and would love to use it to replace all the rusting galvanized metal water supply lines. The main advantage for me is that a PEX manifold and homerun-style system would give both apartments equal water pressure during use ( ie. I don’t get a cold shower while my downstairs renter does the dishes) BUT Chicago apparently doesn’t allow PEX as a potable water supply line. It’s not illegal to install but it is not considered code approved. So my long winded question is, is it worth the risk and just installing PEX, with the hope that soon Chicago will allow it? Is there a way to design a copper pipe system that is (relatively) affordable and provides even pressure, efficient hot water wait times, and doesn’t waste material?

As PEX is generally accepted in all 50 states and other major cities., It’s a very frustrating day to be a Chicagoan.

Would love some advice. thanks,

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  1. user-2890856 | | #1

    Lessen the pressure loss as much as possible . Try this ,, NO 1/2" TEES . That is extreme however , could be possible that the old galvy is just restricted a whole lot . If that is the case , just don't put more than a simple bathroom group on 1/2" pipe , that should be sufficient with pressure greater than 45# . If you have less than 45# I would say no more than 2 fixtures on 1/2" pipe .
    It does kinda amaze that galvanized steel is still allowed by many codes for Potable water while many larger cities prohibit pex .
    Everyone should watch plumbing home runs from a central location also . I have seen many run excessive lengths and waste lots of water while waiting for hot at the fixture .

  2. GBA Editor
    Martin Holladay | | #2

    The easiest way to solve the "cold shower when my neighbor does the dishes" problem is to install a pressure-balance shower valve.

    Home-run plumbing systems have advantages and disadvantages, as Richard has pointed out. But if you like the idea of a home-run plumbing system, you don't have to use PEX to install one. You can use copper tubing for a home-run system; you just have to make your own manifold. If you want to reduce the number of 90 degree ells, you can use flexible soft copper tubing.

  3. alamont | | #3

    Thanks for the responses. Would it make sense to build a manifold that goes from the city main supply line to 4 separate 3/4 lines, one for each floor (basement,1st, 2nd, attic). Each 3/4 trunk would then branch off at it's respective floor in 1/2" to all the fixtures. I think for my needs, a true home-run system in copper would be overkill, but would a manifold separating each floor "trunk" give equal priority to all floors?

    Any advice or resources on building a manifold that takes the 1in city line and is properly sized to have 3/4 outlets. All the manifolds I can find online are for PEX with 1/2 outlets. Does a manifold of this kind need an oversized area before the outlet? For example a 1" pipe feeds a 1.5" or larger section of pipe with outlets that are 3/4"?

  4. GBA Editor
    Martin Holladay | | #4

    Many issues here. You may want to hire a plumber.

    To get started, read this article: Sizing Domestic Water Pipes.

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