Washington’s one-to-one net metering runs on a clock, and at the state’s largest utility that clock has already expired. State law obliges utilities to offer full retail credits only until their cumulative solar capacity reaches 4% of their 1996 peak demand, or until June 30, 2029, whichever comes first. Puget Sound Energy has passed its 4% threshold and is still enrolling new customers on the old terms under Schedule 150, saying only that it will continue until a new rate schedule becomes available. No successor has been filed. If you are a PSE customer thinking about solar, you are inside a window that is open by grace rather than by obligation.
Two Clocks, and One Has Already Run Out
The limit | What it says | Where it stands |
|---|---|---|
Capacity trigger | Full retail credits required until solar reaches 4% of the utility’s 1996 peak demand | PSE has EXCEEDED it. Still enrolling under Schedule 150, voluntarily. |
Calendar backstop | June 30, 2029, whichever comes first | Three years out, and it applies statewide. |
Successor terms | What replaces one-to-one when a utility closes its program | Not filed with the state regulator as of our check. |
Notice | PSE says it will give notice before closing | A commitment, not a statutory guarantee. |
This is one of the clearest genuine act-now cases anywhere, and it is worth being precise about why. It is not that an incentive is expiring on a marketing deadline. It is that the legal obligation which forces your utility to credit you at full retail has already been satisfied at PSE, so the arrangement continues at the company’s discretion. Seattle City Light, Snohomish County PUD and Avista operate under the same statutory framework, and their individual positions need checking directly.
Enter your ZIP code and we will check where your utility stands before you commit.
Check where your utility stands
March 31 Takes Whatever You Banked
The second mechanism to understand is the annual reset. Under RCW 80.60.030, any unused net metering credits are granted to the utility each March 31 without compensation. Washington’s production curve makes that date particularly awkward: the state gets weak winter sun and long summer days, so a system builds credit through summer and autumn and then hands over whatever the winter did not consume, right at the end of the darkest stretch of the year.
Practically that argues for matching the system to your own consumption rather than maximizing annual output, and it makes electric heating, an EV or a heat pump genuinely useful, because winter load is what protects a summer surplus from the March 31 reset.
The Cloudiest Roofs in the Country
Washington produces 1,096 kWh per kW a year around Seattle, among the lowest solar yields in the country and about 40% below Nevada. Washington’s core constraint is sunlight, so you need substantially more hardware to generate the same power. Households use 955 kWh a month, so at $2.88 per watt (as of March 1, 2026) the typical system is 10.46 kW at about $30,114 gross, larger than the typical US system.
What the benchmark buys at each size, gross before incentives:
| System size | Gross cost before incentives at $2.88/W |
|---|---|
| 6 kW | $17,280 |
| 8 kW | $23,040 |
| 10 kW | $28,800 |
| 10.46 kW, the typical Washington system | $30,114 |
| 12 kW | $34,560 |
Consumed as generated, roughly 11,464 kWh a year, modeled at the 14.09¢ statewide average, is worth about $1,615 a year, an 18.6-year payback. Rates are climbing 4.15% a year, which is among the fastest in the country and steadily improves that. The federal residential credit is $0 for owner-purchased systems whose installation is completed after December 31, 2025 under Public Law 119-21. Washington’s compensating advantage is that full retail one-to-one is genuinely valuable while it lasts, which is precisely why the timing question above matters more here than the price question.
That chain runs on the statewide average, which is ranking context rather than a filed rate. Puget Sound Energy, Seattle City Light and the public utility districts each set their own residential rates, so rerun the year and the payback with the rate on your own bill.
Who Should Wait, and Who Should Not
- Do not wait if you are a PSE customer who has already decided. The obligation to credit you at full retail has been met. Waiting is a bet that a company keeps offering something it no longer has to.
- Do wait if your roof needs replacing. An 18.6-year payback does not survive paying to remove and refit the array in year six.
- Think twice on a shaded or north-facing roof. At 1,096 kWh per kW there is less margin here than almost anywhere in the country.
- Ask about the March 31 reset before sizing. A quote maximizing annual production without discussing winter consumption is optimizing the wrong number.
- Check your own utility rather than assuming. Seattle City Light, Snohomish County PUD and Avista each sit at a different point against the same 4% trigger.
Washington Solar Cost FAQs
About $2.88 per watt installed, 25th cheapest in the country as of March 1, 2026. Because Washington has among the weakest sunlight of any state at 1,096 kWh per kW a year, systems are large: typically 10.46 kW, roughly $30,114 before incentives.
It has a defined end. Under RCW chapter 80.60 utilities must offer one-to-one retail credits only until their cumulative solar capacity reaches 4% of their 1996 peak demand, or until June 30, 2029, whichever comes first. Puget Sound Energy has already exceeded its 4% threshold and continues enrolling new customers under Schedule 150 voluntarily, saying it will give notice before closing. No successor schedule has been filed.
Yes. Under RCW 80.60.030 any unused net metering credits are granted to the utility on March 31 each year without compensation. Given Washington’s weak winter sun and long summer days, that timing means a summer surplus has to be consumed over winter or it is lost, which is why winter load such as electric heating or an EV protects the value.
About 18.6 years for a household consuming what it generates at the 14.09¢ retail rate. The obstacle is sunlight rather than price: at 1,096 kWh per kW a year, roughly 40% below Nevada, you need more hardware for the same output. Rates rising 4.15% a year improve that steadily.
If you are a Puget Sound Energy customer who has already decided, waiting carries a real and specific risk: the legal obligation to credit you at full retail has already been satisfied, so the current terms continue at the company’s discretion rather than by requirement. If your roof needs replacing first, sequence that, because an 18.6-year payback does not survive removing and refitting the array partway through.
Your utility’s position against the 4% trigger is the question that matters most here. Enter your ZIP code and we will find out where you stand.
Size around the March 31 reset
Methodology: cost figures use the EcoGen Solar Cost Index for Washington, $2.88 per watt as of March 1, 2026, with payback modeled with no federal residential credit for owner-purchased systems, full retail one-to-one netting, rate escalation at the state 5-year average of 4.15%, 0.5% annual panel degradation, and a 25-year horizon. The statutory framework is read directly from RCW chapter 80.60; PSE’s position past its 4% threshold and its continued enrollment under Schedule 150 are triangulated from utility documentation and reporting rather than a single filing, and no successor schedule was on file with the state regulator at the time of writing.
References & Research Sources
EcoGen America reviewed Washington’s net metering statute and Puget Sound Energy schedule documentation, federal electricity price and utility datasets, Census home-value data, and federal tax guidance for this Washington solar cost guide. Sources were accessed between June 10 and August 17, 2026, unless another date is listed below.
- Washington State Legislature. RCW Chapter 80.60. Net metering statute, including the 4% of 1996 peak demand trigger, the June 30, 2029 backstop, and the March 31 forfeiture of unused credits. Accessed June 10, 2026.
- Puget Sound Energy (PSE). Schedule 150 Documentation. Net metering schedule and PSE statements on continuing enrollment past the capacity threshold. Accessed June 10, 2026.
- U.S. Energy Information Administration (EIA). Electric Power Monthly, Table 5.6.A. Average residential electricity prices by state, March 2026 edition. Accessed June 10, 2026.
- U.S. Energy Information Administration (EIA). Form EIA-861: Annual Electric Power Industry Report, 2024. Residential customer counts for Puget Sound Energy, Seattle City Light, Snohomish County PUD, and Avista. Accessed June 10, 2026.
- U.S. Census Bureau. American Community Survey, 2024. Median home value data used for cost-to-value context. Accessed June 11, 2026.
- Internal Revenue Service (IRS). One, Big, Beautiful Bill Provisions. Guidance on Public Law 119-21, including termination of the Section 25D residential credit for systems whose installation is completed after December 31, 2025. Accessed August 15, 2026.
