My first issue is that when the sprinklers come on, there is a significant drop in water pressure in the sink, shower, etc. I checked the sprinkler lines and there are no obvious leaks (i.e. holes in the ground).
Part II of my problems is varying pressure in different sprinkler zones. There is no pressure in sprinkler zone 1 (sprinkler heads do not come up but dribble water), 1/2 pressure in sprinkler zone 2 (sprinkler heads come up but are at 1/2 flow), while sprinkler zone 3 has full pressure.
The sprinkler repair company wants to add a pressure regular to the line to the sprinklers (runs at over 100 psi when it should be 75 psi) and split sprinkler zone 1 into two zones due to the # of sprinkler heads on this zone. However this does not answer why sprinkler zone 2 is at 1/2 pressure.
Ironically, the house was built in 2009 and for the past 5 years, including last year, the sprinklers ran fine with no water pressure drop problems.