The Honolulu rule
DPP's Building Permit Requirements page (read 23 October 2026) requires a permit for "Any electrical work or plumbing work that is not exempted" (ROH 18-3.1). The plumbing exemption is narrow: "Plumbing repair work performed by a licensed plumbing contractor which does not exceed $2,500 in any 12-month period." A new solar water heater is an installation, not a repair, and DPP gives it its own permit: its step-by-step solar guide says that under "Special Category Permit" you "will find several permits to choose from. This includes EV Chargers, Solar PV, and Solar Water Heater."
| Route | When it applies | What happens |
|---|---|---|
| Quick (Instant Online) Permit | Estimated value of work no more than $75,000; flood zone D, X or XS; no blocking advisory on the parcel | Issued once paid, no plan review (Instant Online Permits) |
| Permit with plans | Anything outside those limits | Plan review, then issue |
DPP's Solar Permits page tells applicants, "for all solar permits, please select 'Yes' for the first question" on the Quick Permit's first page. That page is written mostly for PV; if your parcel is in a flood zone or the HNL Build flow sends you to plans, email HNLBuild@honolulu.gov before you book the installer.
New homes: the state requirement
HRS 196-6.5 says that on or after January 1, 2010, "no building permit shall be issued for a new single-family dwelling that does not include a solar water heater system" unless the Hawaii State Energy Office approves a variance. A variance must come from a licensed architect or mechanical engineer and rests on poor solar resource, life-cycle cost, another renewable system for water heating, or a gas tankless heater with at least one other gas appliance. The new-home side is covered in the Honolulu new home permit.
Who files it
A licensed contractor. DCCA says a Hawaii contractor's license is required "for any project that requires a building, electrical or plumbing permit" (DCCA PVL). The plumbing connection needs a C-37 plumbing contractor; the Honolulu contractor license lookup covers the classes and the free search. In HNL Build, each contractor on the application gets an email to approve it, and DPP's guide says that is required before the application is processed.
What it costs
ROH Table 18-A prices building permits by the total estimated value of work:
| Estimated value | Building permit fee |
|---|---|
| $500.01–$1,000 | $8 + $2.50 per $100 or fraction |
| $1,000.01–$20,000 | $12 + $2.20 per $100 or fraction |
| $20,000.01–$50,000 | $82 + $18 per $1,000 or fraction |
At $4,000, the usual filed value, that is $12 + 40 × $2.20 = $100; at $7,200, near the top of the middle half of firms, $170 (our arithmetic). DPP says HNL Build displays all fees before payment; card payments carry a 2.35% service fee.
How to apply in HNL Build
- In HNL Build, start a new building permit and choose Special Category Permit, then Solar Water Heater.
- Answer the Quick Permit questions; check the flood zone and parcel warnings first.
- Add the owner and every contractor; each contractor approves by email.
- Pay, and after the install check in HNL Build that the permit has closed.
What 2,274 Oʻahu solar water heater permits show
| Measure | Solar water heating |
|---|---|
| Permits on homes, July 2022 to June 2025 | 2,274 |
| Firms | 30 |
| Firms with a permit in the last 12 months | 18 |
| Share of permits held by the 5 busiest firms | 64.2% |
| Usual filed value (middle half of firms) | $4,000 ($3,800 to $7,200) |
| Closed (permits a year or more old) | 70.2% |
| Usual days from issue to close | 225 |
| Firms with 10+ permits: 10th / 90th percentile closed | 27.3% / 91.3% |
| Busiest / quietest month | December (110) / January (82) |
This is a small trade with a wide gap between firms. Five firms hold 64.2% of permits, and among the 17 with 10 or more, the 10th-percentile firm closed 27.3% while the 90th closed 91.3%. For a job usually filed at $4,000, 225 days to close is long; ask your installer when the inspection will be booked, and check the permit status before the final payment. Prices are on Honolulu solar water heating cost; monthly counts on Honolulu permit statistics.
See every Oʻahu solar water heater installer by permits closed →
Before you hire
Compare firms on the Honolulu solar water heating list. PV panels are a separate permit, covered in Honolulu solar permit and hiring a solar installer in Honolulu. Other cities' water heater rules are in do I need a permit for a water heater; national prices in water heater replacement cost.
What this does not tell you
DPP's open data ends in June 2025, so this is a three-year snapshot that stops there. Filed values are the contractor's figure. We have no license match for Honolulu firms, so check each one on DCCA's search yourself.
How we know this
Permit routes are quoted from DPP's Building Permit Requirements, Instant Online Permits and Solar Permits pages and its step-by-step solar guide; fees from ROH Table 18-A, with the $4,000 and $7,200 examples as our arithmetic; the new-home rule from HRS 196-6.5; the license rule from DCCA; read 22 and 23 October 2026. Counts are City & County of Honolulu building permits on homes classified as solar water heating, July 2022 to June 2025; closed share uses permits a year or more old.
Numbers come from City & County of Honolulu building permits (DPP), data through July 1, 2025. Nobody paid to be on this page and nobody can.
Questions
- Do I need a permit for a solar water heater in Honolulu?
Yes. DPP's step-by-step solar guide lists Solar Water Heater among the Special Category Permits in HNL Build, alongside solar PV and EV chargers, and Honolulu requires a permit for plumbing work that is not exempt.
- How much is a solar water heater permit in Honolulu?
Building permit fees follow ROH Table 18-A by the value of the work. Between $1,000.01 and $20,000 it is $12 plus $2.20 per $100; on the usual $4,000 job in our file that is about $100, by our arithmetic. HNL Build shows the fee before you pay.
- Who applies for a solar water heater permit on Oʻahu?
A licensed contractor in practice: Hawaii's licensing division says a contractor license is required for any project that needs a building, electrical or plumbing permit, and HNL Build asks each contractor on the application to approve it.
- Is a solar water heater required on a new house in Hawaii?
Yes, unless the state energy office grants a variance. HRS 196-6.5 says no building permit is issued for a new single-family dwelling after January 1, 2010 without a solar water heater system, with variances for poor sun, cost, another renewable source, or a gas tankless heater with another gas appliance.
- How long does a solar water heater permit take to close in Honolulu?
Longer than the install. The usual Oʻahu solar water heater permit in our file closed 225 days after issue, and only 70.2% of those a year or more old had closed.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Home improvement costs in Honolulu, HI: what 11 kinds of jobs were filed at (2022–2025 permits)
- Do I need an electrical permit in Honolulu? The $2,500 repair exemption, HNL Build and closing times
- Do I need a permit for a home addition in Honolulu? Plans, stamped drawings, the Table 18-A fee and other agency reviews
- Do I need a permit to build a house in Honolulu? Plans, the Table 18-A fee, the solar water heater rule and owner-builders
- Do I need an HVAC permit in Wichita? MABCD's mechanical permit, Table K fees and 5,956 permits
- Do I need a plumbing permit in Wichita? MABCD's Table H fees, the homeowner exam and 11,195 permits
For one city
- Hiring a solar installer in Honolulu: the DCCA license, the permit, and what 16,000 solar permits show
- Building an ADU or ohana unit in Honolulu: the pre-check form, the recorded covenant, converting an old structure, and what permits show
- Honolulu building permit search: HNL Build, TMK lookup and old records
- Step-By-Step Guide: How to Apply for a Solar Permit — Honolulu DPP (PDF) (accessed 2026-10-23)
- Solar Permits — Honolulu Department of Planning and Permitting (accessed 2026-10-23)
- Building Permit Requirements — Honolulu DPP (accessed 2026-10-23)
- Instant Online Building Permits — Honolulu DPP (accessed 2026-10-23)
- ROH Chapter 18, Table 18-A: Fees for Permits — Revised Ordinances of Honolulu (accessed 2026-10-23)
- HRS 196-6.5 Solar water heater system required for new single-family residential construction (accessed 2026-10-23)
- Hire a Licensed Contractor — DCCA Professional and Vocational Licensing (2026-10-22)