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Housing Action Plan — Context Module 8

Why Sequence Matters:
Item Dependencies in the HAP

Not all 148 Housing Action Plan items are equally ready to implement. Some items are preconditions for others — completing them out of order wastes effort or creates conflicts. This module maps the key dependency relationships to inform triage sequencing.

A dependency relationship means that Item B cannot be fully implemented — or its impact is substantially diminished — until Item A is complete. Triage that ignores dependencies risks selecting items that look high-priority in isolation but are blocked by upstream work that hasn't been scheduled.

Dependency chains — hover items for detail, filter by category

Filter:

Sequencing logic — three clusters for triage

Foundation items — complete first

These items are preconditions for multiple downstream items. Delaying them delays everything that depends on them. Triage should treat these as high-priority regardless of their individual complexity.

P-5 Design guideline clarity Z-8 Lot size & dimensions PL-1 Public land inventory Z-30 Workforce housing ord. P-12 Permit timeline audit

Mid-stream items — need foundation

These items are ready to move once foundation items are in place. Many are the most visible and politically significant items in the HAP — they benefit from having upstream work done first.

Z-2 ADU ordinance Z-5 Missing middle allowances Z-9 Cottage housing Z-6 Density bonus Z-4 Parking reform

Downstream items — complex chains

These items have multiple upstream dependencies or require significant institutional capacity before implementation is meaningful. Scheduling them too early creates delays and dilutes effort.

I-22 Shared equity I-22 Shared equity program Z-11 Form-based code reform P-6 Pre-application meetings HTF-1 Housing Trust Fund

For triage: The July 2026 Council deadline creates pressure to show early progress. Foundation items are the right answer to that pressure — they're the ones that unlock the rest of the plan. Selecting only visible mid-stream items without clearing upstream dependencies risks delivering activity without impact.

Sequencing · status changed
The I-20 prerequisite failed in commercial districts
This map records I-20 (land value capture and anti-speculation) as a precondition: it had to be in active development before missing middle allowances and single-family zone reform proceeded to ordinance drafting. The logic was that upzoning without capture raises land prices and makes affordable acquisition harder.

For commercially zoned land that sequence has already failed. Chapters 319 and 329 of 2026 upzoned Portsmouth’s commercial districts by state action, effective July 1 and September 13, with no capture mechanism in place and no local decision to sequence. The precondition was not overridden — it was bypassed.

Two things follow. The dependency still holds for residential districts, where Portsmouth retains control of the timing. And the commercial districts now function as a natural experiment: if land prices there move as I-20 predicts, that is evidence for the sequencing argument rather than an assertion of it. Worth measuring deliberately.