ROH Chapter 21

R-3.5 Residential

Honolulu's smallest standard single-family residential district. Designed for urban infill and older neighborhood lots in central Oahu. The 3,500 sf minimum lot area and 50% coverage limit make lot coverage the dominant constraint on most R-3.5 projects.

Common locations: Kalihi, Palama, Kalihi Valley, Sand Island adjacent areas, and older Honolulu neighborhoods platted before post-war standards.

Development standards

Standard	Requirement
Minimum lot area	3,500 sf
Front yard	10 ft min
Rear yard	5 ft min
Interior side yard	5 ft min
Street-side yard	10 ft min
Max lot coverage	50%
Max building height	30 ft
FAR limit	None

No explicit FAR cap — lot coverage (50%) and setbacks are the binding constraints.

Source: ROH §21-3.10-1 (R-3.5 district standards)

Sample calculation

Lot area3,500 sf

Max coverage (50%)1,750 sf

Typical house footprint1,100–1,400 sf

Coverage headroom350–650 sf remaining

Buildable envelope (50 × 70 ft lot, interior)40 ft wide × 55 ft deep = 2,200 sf

Common DPP plan-check violations

1Lot coverage exceeding 50% due to proposed covered lanai or garage

2Front yard setback measured to eave overhang exceeding 18 inches

3Second-floor addition projecting beyond the first-floor footprint into the front yard

4Accessory structure not meeting 5-ft interior side setback

5Parking table missing from site plan

Key exceptions and reliefs

—Accessory structures under 200 sf and 15 ft high may use 3-ft rear and side setbacks

—Roof overhangs up to 18 in from face of wall do not count toward setback or lot coverage

—Open-top trellises and pergolas do not count toward lot coverage

—Steps, uncovered porches less than 30 in above grade may encroach into required yards

Run the zoning calculator →

Enter your lot dimensions and proposed footprint — instant lot coverage, envelope, and FAR check for R-3.5.

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Upload your drawings for a full citation-anchored compliance report covering R-3.5 zoning + IBC in ~30 min.

← All zoning districts

Development standards are based on ROH Chapter 21 as of May 2026. Verify all values against the current DPP-adopted code before relying on them. Overlay districts (SMA, flood zone, historic), special area requirements, and neighborhood-specific provisions may impose additional standards not reflected here.