I have a whole house water system that uses a pressure regulater. the whole system is about 7 years old. for the last 6 months or so when the water is turned on at any of the inside faucets or fixtures, the water pulsates hard enough to shake the pipes. the pulsating does not occur right after the water is shut-off so i do not think it is water hammer. i think it may be the water pressure regulator. would a failed regulator cause this problem?

Sound like "air" is in the system. That will be your cheapest fix before changing parts.
All the Best.

A water heater is only designed to last about 6 or 7 years. Replace it!

Copy following link for troubleshoot walk-thru:
http://waterheatertimer.org/Low-hot-water-pressure.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

State, Kenmore, Reliance, Ace , Ambassador, Barnett, Century, Crosley, Energy Stretcher, Freedom, Freedom/Nipsco, Hardware House, Master Plumber/True 5, Mission, Nationaline, Patriot, Penfield, President, Regency, Century, The Plumbery, Thermo-king, TopLine
1-letter month followed by 2-digit year

So it was manufactued in 1994. Most water heaters will last 5-10 years for gas and 10-15 for electric unless they receive yearly maintenance (flushing tank, cleaning) so it is already past its expected life span.

That being said, an electric water heater is more costly than a gas one. If I was in your place I would start saving to replace the unit with a tankless gas water heater, as soon as the house closed.

It sounds as if the thermocouple has failed and allowed the tank to contract, releasing
the rust from inside. I would recommend replacing the entire unit before it breaks as most
units are only warranted for about 6 to 9 years. Hope this helps.

I can't tell if you have tankless or tank heater.
Rheem has gone big into tankless the last few years and maybe first models don't have parts any more.

Even so, Rheen probably sells the whole burner assembly.
Most plumbers prefer to replace whole assembly so they're not doing a call-back next month.
Check with Rheem for whole assembly.

Another option is to roll the Rheem heater out of the way and install generic brand from Ace, Home Depot, Sears, or Lowes. Read manual cover to cover to prevent failure. Keep dust, lint and chemicals out of same room. Loosen anode rod before installing. Connect ground wire jumper to hot and cold pipes.
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html
Fix the Rheem when parts become available, or use it as tempering tank to passively preheat incoming cold water, or set tank in wood box with glass cover and make passive solar tank.

Water system had a break somewhere and dirt got in the line. Change filters.

http://www.buyerschoiceinspections.com/water-heater-ages
There seem to be 2 possible answers: Servi-star vs Servistar

Answer #1: Servi-star by American
1st 2 digits are year, 2nd 2 digits are week

This means water heater was made year 2004, 96th week ....it seems wrong.

Answer #2: Servistar by Craftmaster
1st 2 digits are month, 2nd 2 digits are year

This would mean your water heater was made 4th month of 1996

Which answer is true? 6 years old or 14 years old
If tank had 12 year warranty and came with 2 anode rods, and you have good water, and no stray current on pipes, then tank can last 14 years.
If tank had 6 year warranty and came with one anode rod, and you have hard water and a water softener, and you never changed anode rod or drained tank, then 6 years is a long life for the tank.

call whirlpool and tell them ur problem.....i am sure they will help you

it comes on when the pressure changes so when you open another faucet it changes the pressure and makes it come on,, check your pressure regulator valve on the main line comming into the house it has a screw in the center, if you have a pressue gage put it on either the water heater drain or out side hose bib , check the pressure when turning water on and off if it changes more then 5 lbs you need to change your prv valve. pressure regulator valve,