My outside faucet pressure is low. I can only water at night. When I am watering and we turn on the washer the pressure is so low that the sprinker does not work... can you help

My outside faucet pressure is low. I can only water at night. When i am watering and we turn on the washer the pressure is so low that the sprinker does not work ...can you help

How old is your home and what kind of pipe do tou have? PLastic, copper or galivanized? Let me know. Regards, Tom

3 yrs old. And plastic pipes...

I should also have asked, "What's the PSI enteruing yoiur house?"
The pressure's OK in the house and not outside? Did this happen all at once or did it come on gradually? Waiting on you. Regards, Tom