Oregon homeowners have a net metering explainer on this site. Washington homeowners deserve the same, because the rules are genuinely different — and the difference that matters most is a single date on the calendar: 31 March.
How does net metering work in Washington?
When your array makes more than the house is using, the surplus goes onto the grid and your meter credits you for it. When you draw more than you make — at night, in December — you use those credits before you buy power again. The mechanism is set out in state law under RCW 80.60.
You are not selling power in any meaningful sense. You are banking kilowatt-hours against your own later use, which is why sizing a system to your consumption matters more than sizing it to your roof.
What is the 31 March balance date?
This is the part people miss. Washington net metering accounts have an annual balance date of 31 March. Credits you have accumulated and not used are reconciled then rather than rolling forward indefinitely.
The date comes straight from the statute. RCW 80.60.030(5): “On March 31st of each calendar year, any remaining unused credits for kilowatt-hours accumulated during the previous year shall be granted to the electric utility, without any compensation to the customer-generator.” Cowlitz PUD’s own net metering page uses the same date — credits are “zeroed out” on March 31.
The timing is actually well matched to how solar behaves here. You build credit through the bright half of the year, draw it down through the dark half, and arrive at the end of March having used what you banked. What it does mean is that a system deliberately oversized to bank a big surplus is banking something with a shelf life — another reason to size against real annual usage rather than available roof.
How big a system can I net meter?
Systems up to 100 kilowatts qualify under the state programme. That is far beyond any home installation and comfortable for most small commercial roofs, so for residential purposes it is effectively not a constraint.
Does my utility have to offer it?
Washington law requires utilities to offer net metering, and the Utilities and Transportation Commission regulates the three investor-owned utilities in the state — Avista, Pacific Power and Puget Sound Energy. There is also a cumulative capacity limit written into the law, set as a share of each utility’s peak demand.
In our service area, though, most homes are served by consumer-owned public utility districts rather than an investor-owned company. Clark Public Utilities and Cowlitz PUD set their own programme terms within the law, and the details — how excess is credited, what the interconnection application looks like, what happens at the balance date — are theirs. We confirm the current terms with your specific utility before designing a system rather than assuming a statewide default.
How is this different from Oregon?
The mechanics rhyme, but the terms and the reconciliation timing differ, and the incentive landscape around them differs a great deal more. Oregon’s Energy Trust incentives, for example, are funded by and limited to Portland General Electric and Pacific Power customers. Our Oregon net metering explainer covers that side.
If you own property on both sides of the river — which is common enough around Vancouver and Portland — treat them as two separate questions rather than one.
What does this mean for sizing?
Three practical rules follow from the way Washington net metering works:
- Size against twelve months of usage, not against the largest array your roof could hold
- Account for loads you are about to add — a heat pump or an EV changes the target materially
- Use what you make when you can. A kilowatt-hour consumed as it is produced is worth more than one exported and reclaimed later, so shifting the dishwasher, the water heater or the car charging into daylight quietly improves the return
Frequently Asked Questions
Does a battery change how net metering works?
Yes, and in a way that suits Washington’s 31 March reset. With a battery, surplus daytime production charges the battery first; only what the battery cannot hold is exported and banked as a credit. In the evening you draw the battery down before you draw on the grid or on your banked credits. Net metering still applies to everything that crosses the meter — the battery just shrinks how much does.
A worked example. On a clear afternoon a system produces 5 kWh while the house uses 2 kWh. The spare 3 kWh charges the battery; if the battery is already full, that 3 kWh goes to the grid as credit. The next morning is overcast: the panels make 1 kWh and the house needs 4 kWh. The battery covers most of the gap, the grid covers the rest, and the meter records only that small net draw. Over a year the household pays for very little grid electricity — and because more of the surplus is used at home rather than banked, less of it is exposed at the March balance date.
The battery also gives you the one thing net metering cannot: power during an outage. Grid-tied solar without storage shuts down when the grid goes down.
How do I read a net meter?
A bidirectional meter keeps two running totals: energy delivered to you and energy received from you. Your bill shows the difference. Many utilities also print the banked credit balance on the statement, so you can watch it build through summer and run down through winter ahead of the 31 March reconciliation; if yours does not, ask. If your meter only shows one number, ask your utility whether it has been swapped for a bidirectional unit — that swap is typically part of the interconnection process.
Is there a downside to net metering?
Two practical ones. Credits are kilowatt-hours, not cash, and they do not carry forward indefinitely — so a system sized to overproduce all year loses the surplus at the balance date. And because your utility sets the specific terms within state law, the rules can differ between Clark PUD, Cowlitz PUD and the investor-owned utilities. Neither is a reason not to do it; both are reasons to size the system to your actual usage and to confirm your utility’s terms before design.
How does net metering work in Washington state?
Surplus production goes to the grid and credits your account; you draw those credits down when you use more than you produce. It is governed by RCW 80.60, and the credits are kilowatt-hours banked against your own later use rather than a cash payment.
When do Washington net metering credits expire?
Net metering accounts have an annual balance date of 31 March, when accumulated credits are reconciled rather than carried forward indefinitely. That timing suits the Pacific Northwest solar year, but it is a reason not to deliberately oversize a system.
What size solar system can be net metered in Washington?
Up to 100 kilowatts qualifies under the state programme — far above any residential installation, so for homes it is not a practical limit.
Does Clark PUD or Cowlitz PUD offer net metering?
Consumer-owned utilities operate their own programmes within state law, so the specific terms are set by your utility rather than by the UTC, which regulates the three investor-owned utilities. We confirm current terms with your utility before designing a system.
Is Washington net metering the same as Oregon’s?
The mechanics are similar but the terms and reconciliation timing differ, and the surrounding incentives differ more — Oregon’s Energy Trust programmes are limited to PGE and Pacific Power customers. Treat properties on either side of the river as separate questions.
Corrected September 12, 2026: an earlier version of this page gave 30 April as the annual balance date. The correct date under RCW 80.60.030 is March 31.
Not sure how your utility handles it?
Call 360-313-7190 and we will check the current terms for your address before anyone talks about system size. Sunbridge Solar installs across Clark, Cowlitz, Skamania and Klickitat counties — see our Washington solar installers page for the towns and what each utility allows — and in the Portland area.
