What are these valves and can I use them to...

[E150GT]

Adjust my home water pressure down? I recently learned that you can control the water pressure coming in to your home with a regulator. I never knew that until my rental property had a pipe leak in the yard and i found a valve that regulates pressure. That got me thinking and I decided to check the pressure at a hose bib on my residence. It shows 70 psi. I read you shouldn’t have more than 60 psi. In my yard I found two little boxes that have some valves I’m assuming and I don’t know what they are or if I can use them to adjust my pressure. Pictures below.

 

[gregk24]

Top picture looks like a backflow preventer, don't think it can be used to adjust pressure.

 

[KJSmith]

Yep, looks like a backflow preventer.
The other is zone valve.
Both are tied into your sprinkler system, not your house.

 

[E150GT]

Hmmm. Maybe the house doesn’t have such a valve to regulate the pressure.

 

[walterjay]

The first pic is an irrigation system backflow preventer. The second pic is a electric selonoid zone valve which can regulate water flow but not water pressure presumably to a sprinkler system.
70 psi is not outrageously high. Most water fixtures can handle up to 80 psi. If you want to lower it get a pressure reducing valve from a plumbing supply store. They usually cost about $59.00 Most plumbers will charge about $250 and up in my area to supply and install one.

 

[Stelth]

80 psi and above is considered excessive. Pressure in the 50-60 psi range will make your system quieter, and help plumbing equipment last longer. Like Walterjay said, 70 psi isn’t outrageous, but municipal pressures can go pretty high in periods of low demand, which is a good reason to have a regulator.

 

[Lyman]

If you have a regulator they are normally right by the valve to turn your water main on and off.