Hawaiʻi County Solar Water Heaters: Review Changes to an Approved Design

Identify What the Existing Approval Covers

Collect the approved plans, water-heater description and any state variance associated with the house. Record where the tank and collectors are located and whether the proposal changes the technology, position or both. A quote labeled “water heater replacement” can conceal a much larger design change.

The county memorandum’s table is dated March 21, 2024 and addresses changes to permits issued for solar water heaters. Ask the Building Division how it applies to your permit and existing home. Do not use a new-construction rule to decide every maintenance question.

Distinguish Panel Moves From Tank and Structure Changes

The county table treats a panel-location change differently from moving a ground-level tank onto the roof. It identifies design-professional documentation and revised-plan requirements for different scenarios. Bring the proposed arrangement to the reviewer before assuming that the installer can handle it solely through a field adjustment.

For a roof tank, ask the designer to explain the support and attachment scope. For relocated collectors, identify the piping route and roof penetrations. The proposal should say who repairs old attachment points and weatherproofs the new ones, including work that falls outside the plumber’s quoted equipment installation.

Check State Variance Questions Before a Technology Swap

The Hawaiʻi State Energy Office describes a solar-water-heating requirement for new single-family dwellings, with a variance process. That precise scope matters: it is not a statement that every existing household must install a new solar system.

The county change memorandum identifies variance documentation for certain substitutions involving electric, gas or hybrid systems. If your project changes an approved solar design, ask the county and the design professional whether an existing variance is sufficient or new review is needed. Settle that question before buying a replacement that cannot simply be installed under the old paperwork. If a variance is needed, identify the Hawaiʻi-licensed architect or mechanical engineer submitting it and review the State Energy Office’s current workbook and floor-plan instructions together.

• Does this proposal alter an approved solar-water-heating design?
• Which revision, professional letter or variance applies to this case?
• Who supplies updated electrical and plumbing contractor declarations?

Plan the Temporary Hot-Water and Final Handoff

Ask the installer how long the household may be without hot water and how the work will be staged if roofing, plumbing and electrical crews are involved. Have them identify any temporary arrangement that needs review. A promised installation date should account for required documents and access to the equipment.

Keep the final system model, controls, approved changes and inspection results together. Request a demonstration of normal operation and the procedure for reporting a leak or loss of hot water. Retain documentation of abandoned roof connections so future roofing work does not mistake them for active equipment.

Sources And Local Resources

Official sources checked October 17, 2026. Confirm current requirements with the authority responsible for your property.

• Hawaiʻi County Solar Water Heater Change MemorandumMemorandum BLD-ADM-015R: PDF page 1 explains design changes; page 2, dated March 21, 2024, compares revision, professional-letter, variance and plan needs. Confirm applicability to the existing permit.
• Hawaiʻi State Energy Office Solar Water Heat VarianceState requirement is framed for new single-family dwellings and provides a variance route; does not establish a universal existing-home retrofit requirement.