Plumbing in the Home/Water Valve Shutoff
I live in a single family ranch home in New Jersey. When my wife and I go on vacation for a couple of weeks in the winter, I turn off the main water valve to the house so in case a pipe bursts, we won't come home to a flood. However, we plan to be away from home for 3 weeks during August and I'm wondering if it's safe to only close the inside water valves and leave the outside water open. I say this because I don't want to burn out my lawn if we have a heat wave and no rain while we're away. I would like to keep the underground sprinkler system working and this won't happen if I shut off the main water valve. I would appreciate your advice. Thank you.
Plumbers have a lot of latitude when it comes to setting up a main water service. Unfortunately, most will set it up correctly in my view.
In my opinion, if one contemplates having an irrigation system, the main service and shutoffs should be plugged so that each can be shut off independently and arrange so that their irrigation system can be kept on when the house supply is turned off.
There is always the danger of burst pipes or failed fixture supply lines while you are away. One way to mitigate this problem is to replace all of the fixture supplies, including the washing machine hoses, with braided stainless steel lines that are less likely to fail.
In my view, rubber washer hoses are a disaster waiting to happen. If you read almost any washing machine installation manual, it will tell you to turn off the water supply in between uses. People rarely do this and end up with a flooded house when the 10-year-old rubber washer hose gives up the ghost. Murphy's Law says it's bound to happen the day after you leave on a two-week vacation! LOL.
Turning off the angle stops and washer supply faucets can help mitigate the problem of the bursting supply. Of course it does nothing to protect against a burst pipe which is more likely in the wintertime but still possible even in the summer.
I would consider getting your main service reconfigured so that you can leave your sprinklers on while turning off the house supply.