The core distinction: A by-right project meets the rules as written — staff reviews the application against objective standards and issues a permit. A discretionary project does not meet those rules and must go before a board (typically the ZBA) to request an exception. The board has latitude to approve, condition, or deny. That latitude is the variable that shapes developer behavior before an application is even filed.
The Two Paths — click any step to expand
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By-Right Approval
1
Project meets zoning standards
Use type, density, height, setbacks, and parking are all permitted as-of-right in the applicable zone. No special findings required.
No exceptions needed
2
Submit application to Planning staff
Application reviewed against objective, measurable standards. Staff cannot deny a project that meets all code requirements.
Weeks, not months
3
Staff technical review
Planning reviews for completeness and code compliance. May include DPW, fire, building — all objective criteria. Public comment is not part of merit review.
Predictable timeline
4
Permit issued
If the project meets objective standards, the permit must be issued. Outcome is predictable before the application is filed.
Low uncertainty
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Discretionary Approval
1
Project doesn't meet current zoning
The project type, density, or form is not permitted as-of-right. A variance or special exception from the ZBA, or conditional use approval from the Planning Board, is required.
Exception required
2
Prepare variance application
Applicant must document "unnecessary hardship" or meet other variance standards. This often requires legal counsel and expert testimony — adding cost before a single board hearing.
Legal & consulting costs
3
Public hearing before ZBA or Planning Board
Board members apply subjective standards. Abutters and neighbors can testify in opposition. Outcome depends on board composition, community sentiment, and the specific project. Findings must be written under RSA 676:3,I but quality of findings varies.
Outcome uncertain
Months of lead time
4
Approval, denial, or conditional approval
Conditions can significantly change project economics. Denial triggers appeal rights. Either path adds time and cost — and the uncertainty alone is enough to prevent some projects from being proposed at all.
Possible appeal / litigation
Higher carrying costs
Why the distinction matters for housing production
6–18 mo.
Time difference
Discretionary review can add 6 to 18 months to a project timeline. In a high-cost market, carrying costs during that period can make a project infeasible.
Chilling effect
Proposals never filed
The most significant impact is invisible: projects that developers choose not to pursue because the approval path is too risky or expensive to justify the attempt.
RSA 672:1 III-e
Legal obligation
NH law prohibits municipal ordinances that unreasonably discourage housing. Zoning that forces housing into variance processes may conflict with this standard.
Scenario explorer — same project, two paths
Accessory Dwelling Unit — single-family lot
A homeowner wants to add an ADU above their garage on a residential lot. ADUs are now by-right in Portsmouth — this scenario illustrates why that change matters.
By-right — Portsmouth today (post-March 2026)
ADU allowed by-right under HB 577 (July 2025) and Portsmouth's March 2026 ordinance update
Building permit submitted directly to staff — no ZBA, no special exception
Review is objective: lot coverage, height, setbacks only
Permit issued in weeks; homeowner knows outcome before applying
Discretionary — Portsmouth before March 2026
ADU triggered special exception or variance requirement in most zones
Homeowner retained attorney; filed with ZBA
Public hearing scheduled — neighbors could oppose
3–6 months minimum; outcome uncertain; many homeowners gave up
Result (by-right — current)
ADU built; housing unit added — the HAP's first tangible win
Result (discretionary — pre-2026)
Many homeowners abandoned the project before filing
Mixed-use infill — ground floor commercial, upper-floor housing
A developer wants to build a 4-story mixed-use building on an underutilized downtown parcel.
If permitted by-right
Use type, height, and density all meet zone standards
Site plan review is technical; focused on circulation, drainage, design standards
Developer can model project economics with confidence before land acquisition
Timeline is known; financing can be structured accordingly
Under current Portsmouth rules (some zones)
Density or height requires variance; use may require special exception
Months of pre-application work before hearing; expert testimony needed
Neighbors can condition or defeat approval; board outcome unpredictable
Lenders discount discretionary approvals; financing harder to secure before approval
Result (by-right)
Project advances; financing secured; units built
Result (discretionary)
Project modified to reduce density, or abandoned; fewer units
Duplex conversion — existing single-family home
An owner wants to convert a large older home into a two-unit structure.
If permitted by-right
Two-family use is allowed in zone — building permit only
No public hearing; conversion reviewed against objective building code
Owner can begin planning and financing with certainty
Second unit added to housing stock in months
Under current Portsmouth rules (most residential zones)
Two-family use not permitted as-of-right; variance or special exception required
ZBA hearing required; findings of hardship must be documented
Neighbor opposition common in single-family zones
Legal costs often approach or exceed renovation cost for modest conversions
Result (by-right)
Conversion completed; ownership housing supply increases
Result (discretionary)
High process cost relative to project value; rarely attempted
Housing Action Plan items that address this
Several HAP items directly target the by-right gap — expanding what's allowed as-of-right in Portsmouth's zoning. Click each to see how.
Z-2 + P-2
ADU ordinance enhancements + Administrative approval for ADUs
The baseline is now met — HB 577 (July 2025) and Portsmouth's March 2026 ordinance update established by-right ADU approval statewide and locally. Z-2 now focuses on enhancements beyond that baseline: expanding ADU standards, addressing dimensional constraints, and ensuring Portsmouth's ordinance is optimized rather than merely compliant. P-2 (administrative approval) is operationally complete.
Z-26
Reduce conditional use permits for housing
Directly targets the discretionary review burden by reducing the categories of housing development that require a conditional use permit. Fewer CUP requirements means more projects can proceed on an administrative, by-right basis.
P-5
Design guideline clarity
Establishes clear, measurable design guidelines that allow more projects to be reviewed administratively against objective standards, reducing the subjective board review of design elements that currently adds discretionary delay and uncertainty.
Z-8
Lot size and dimensional requirement updates
Current minimum lot sizes and dimensional standards force many infill projects into variance territory. Updating these to reflect the typical lot patterns in Portsmouth's built-out neighborhoods removes a common upstream trigger for discretionary review.
Z-4
Parking requirement reform
Parking minimums frequently generate variances in dense neighborhoods where meeting them is physically impossible on existing lots. Reforming parking requirements in walkable and transit-accessible areas removes one of the most common triggers for discretionary review on otherwise conforming projects.
For triage: When evaluating any zoning item in the Housing Action Plan, the threshold question is whether it moves housing production from discretionary to by-right. Items that accomplish this shift have compounding impact — they reduce cost, reduce timeline, and reduce the chilling effect on projects that are never proposed. Items that only modify conditions within a discretionary process have more limited reach.