Rules by state · Washington

Tacoma Power customer owned generation

Their own published program, read and recorded. This outranks the Washington state rule wherever the two differ, because it is the program this utility actually administers.

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How the size is measured

the AC capacity in kW. The customer requirements document states that customer owned generation of not more than 100 kW AC capacity is subject to the net metering requirements, and that anything over 100 kW AC requires a systems impact analysis. The customer service policy leaves the same 100 kW figure bare, and the specific document governs.

Size bands and what each one obliges

Net metered, 100 kW AC or less Size 0 to 100 kW

No application fee, no study deposit and no insurance are published, all confirmed by reading both documents. An electrical permit is purchased from Tacoma Power itself rather than from the county, and it must be obtained before the net meter application is submitted.

  • Electrical permit purchased from Tacoma Power, before the net meter application
  • Visible break blade type safety disconnect in a metal enclosure, padlockable open, within sight of the billing meter
  • Permanent durable labeling of both the billing meter and the safety disconnect
  • The permit holder must be on site at the time of the electrical inspection
Above 100 kW AC to 2,000 kW Size 100.001 to 2000 kW

A systems impact analysis is required above 100 kW AC, and the technical connection requirements apply rather than the net metering requirements. The customer requirements document covers generation of 2,000 kW or less.

  • Systems impact analysis
  • Technical connection requirements rather than net metering requirements

The screens that decide it

Ask the utility this, before you sell it

  1. Is this address in the downtown core network or near a hospital? Either requires pre approval and a systems impact analysis at any size.
  2. How long will review and permission to operate take? Neither document publishes any approval or permission to operate interval.
  3. What does the Tacoma Power electrical permit cost for this job? It is priced under the municipal code rather than in these documents.

Worth knowing before you quote

Unused net metering credits expire every 31 March and the bank resets to zero, so a system commissioned in autumn banks credits it will lose in March. Size and time the sale accordingly. Excess is credited at retail under RCW 80.60. No percentage of consumption cap is published as a rule: the guidance recommending a system that generates no more than average yearly use is advisory language and is not encoded as a limit. No fifteen percent screen and no minimum load test are published; the published gate is a discretionary study by size and location. The safety disconnect is required at every size with no exemption. A production monitoring device is optional and, if used, is provided and installed by the customer. The net meter application is a DocuSign form. Backup only generators must have an inspection department approved protection switch or panel to prevent feeding the distribution system.

Source

Tacoma Power Customer Requirements for Customer Owned Generation, document C-MR-0015 dated 31 March 2026, with the Customer Service Policies section 14.0 effective 1 April 2026 under Resolution U-11593

Read and recorded 2026-09-12. Municipal or public utility, outside its state's interconnection rule. Its own published documents govern. A Washington municipal utility. Washington RCW 80.60 does bind Tacoma Power for net metering, which is where the 100 kW line and the 31 March credit reset come from; the interconnection terms are the utility’s own.

All Washington interconnection rules

What to do with this

Check a real address

The rules below are the general case. Run the free check to see which utility serves a specific address, which tier the system lands in, and what to ask.

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Installers: keep the answer with the job

GridProjeX holds the project from here, with every value tied to the document it came from and the utility and permit tracks run to permission to operate.

How it works for installers
Utilities: see what applicants are told

The same published rules your applicants read here are the ones your queue sees. GridProjeX is the record both sides work from.

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Also from CivyxIQ, if they fit what you already do: SolarProjeX for running the crews and the jobs, and Solar Home so the homeowner can follow their own project. Neither is needed to use the checker.