Losing Water Pressure

[Wpollock]

Residence: 2 story home built in +/- 1996 in Austin,Texas
2 natural gas hot water tanks both located in two different attic spaces above 2nd floor ceilings. Older of the two definitely feeds the kitchen and all bathrooms.It has gradually starting making increased "grumbling/gurgling" noises as it reheats incoming water.
There is high city water pressure in this area as indicated by a pressure reduction regulator located just down stream of the city meter and before entering the house. The regulator in place when I moved in had rusted to the point of leaking and was replaced in July of 2016 by a plumbing company under a home warranty contract. Before it was replaced there was extreme water pressure fluctuation when a valve was opened or toilet was flushed. Now when a valve is opened or a toilet is flushed on either floor, there is extreme loss of pressure at any other sink,shower or toilet.
Any thoughts are appreciated.

 

[Dj2]

What is the indoor water pressure when no water is being used? Take readings in various locations - like the washer faucet, an outdoor hose bibb or the water heater outlet.

Grumbling/gurgling may indicate mineral build up at the bottom of the water heater tank. How old if this WH?

 

[Sponsor]

 

[LLigetfa]

It has gradually starting making increased "grumbling/gurgling" noises as it reheats incoming water.

The noise suggests a buildup of lime scale which can also constrict the outlet of the HWT or clog heat traps. The scale can also get trapped in angle stops or anti-scald pressure balance spools. Fixtures with no anti-scald should see equal pressure on both hot and cold taps.

The first thing to do is to measure the pressure after the regulator while water is being used. A portable GHT pressure gauge can be placed on any convenient hose bib, be it the HWT drain, a washer hookup, or outside tap.