With a 1/3 acre lot, do you have enough lawn and/or garden and so little rainfall that you can justify the costs of an underground sprinkler system or is you purpose for having the system something other than or in addition to watering your lawn/garden such as being able to turn them on to run off neighborhood pets/pests?

If your objective is just to water your lawn/garden, are you interested in considering possible alternatives?

You might consider creating an underground drainage system for your gutter downspouts beneath the area in need of additional water.

If most of your lawn/garden is on one or two adjoining sides, you might create as a separate project (at a centrally located site) one or more outdoor faucets. These can be placed within an insulated (even lockable) box visually hidden within in some decorative garden feature.

Planned in advance, you could link the use of these two projects: Enable your faucets to be used as faucets in the usual way (by adding a hose pipe) and/or enable your faucets to add water to your drainage/irrigation system during times of low rainfall,

There are pipes with holes in the bottom intended to be placed in a gravel filled drainage ditch that could work for irrigation. Not sure if adding soaker hoses within such pipes so you could, as needed, fill them with your outdoor faucet would meet your needs -- but, given the cost of an actual sprinkler system, it is something that might be worth considering even though you might well end up needing to turn your faucet on and off manually, rather than with an electronic control -- but I suspect outdoor faucets don't need annual inspection or fees for it.

Thank you for the response.

Yes, I live in the Seattle area, but for about 3 months in the summer, there are periods of almost no rainfall and really hot sunny weather. So...the irrigation system is used the most during the summer.

The property is really hard to describe. It is up on a hill. It is next to a wooded area and there are several very large pines on the property. The main lawn sits south of the house, but really most of the property has vegetation of one type or another and needs watered at least during the summer. There is a multi-tiered orchard as well that has apple and pear trees.

As for the cost, I don't really think it's going to be horribly expensive since I'll be doing all the labor.

My objective is simply to water my lawn...never even considered the pet/pest thing.

The underground drainage system, which I hadn't considered, sounds possibly more complicated than a sprinkler system. There is already a drainage system in place and I don't really want to mess with it. It is probably already set up to do what you said. Although, sidenote, I bet it is in need of some maintenance. I've noticed that one of the drains is clogged at the downspout. Should I dig that up to clear it?

Thanks again.