On a new construction build down the street, I am interested to know what this is and what it does? We are in California on public water if it makes a difference. enter image description here


A placeholder for the water meter [or a secondary water meter to differentiate internal (& sewer) water from external (just water) uses] is one possibility.

Or for some other (not presently installed) device that mounts with unions, such as a Pressure Reducing Valve (PRV.)

  • I was thinking its a placeholder for easier repair in future. If you remove the black thing, you can service and replace other components fairly quickly? But I do like your idea about future uses...
    – Paul M
    Aug 2 at 21:53
  • Also any idea what the two stub outs can be used for? Im thinking first one from bottom is used for fire sprinklers, what about the next one up? Top one is entering house so thats just house water...
    – Paul M
    Aug 2 at 21:54
  • I speculated and came up with the secondary meter, where the lower would be irrigation use and the upper might be for the water heater, outside, as this is one of those places where water pipes are exposed outside (not a thing we are comfortable with in the winter lands...) - your fire sprinkler idea might be a different logical use for a stub-out that could be before the main meter, if that's not actually upstream of this at the curb/street. But it's just speculating; you could buy some coffee and doughnuts and drop by at break time and learn the actual reasoning.... ;^)
    – Ecnerwal
    Aug 3 at 2:00
  • 1
    Spoke to some plumbing folks on-site, this is a temporary placeholder for PRV. They remove the PRV so it doesn't get clogged with debris during construction period. Was told the lowest stub-out was for inside fire sprinklers and the next one up is for irrigation.
    – Paul M
    Aug 16 at 0:56

Looks like it would be to electrically isolate the home's piping from the city's.

  • would this replace the need of grounding the copper pipe? Or you would still need a ground?
    – Paul M
    Aug 2 at 20:17
  • 1
    I'd assume you would still need a ground, this would just improve safety from things like the neighbors power arcing to their plumbing and carrying in to yours.
    – izzy
    Aug 2 at 20:18

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