Cowlitz County, WA Zoning Overlays & Bonuses: Density Bonus Law (2026)

340, in the PUD chapter's design and development standards, sets the base density formula for a Planned Unit Development: the maximum dwelling units is the net development area divided by the minimum lot size of the underlying zone, except in the rural residential-1, rural residential-2 and rural residential-5 districts, where gross development area is used instead. Net development area is calculated by subtracting land set aside for incidental retail and other nonresidential uses from the total site, then subtracting another 15 percent of the remainder for streets; land set aside for parks, recreation and common open space can still count toward meeting the underlying zone's density.

Subsection B then layers on a density bonus, capped at a maximum of 30 percent above that base, available only if water, sewage disposal and other facilities can accommodate the added density. The county evaluates the bonus against three specific criteria, each with its own percentage: a 10 percent bonus if the PUD provides significant recreation areas such as tennis courts, basketball courts, golf courses, children's play areas, trails, or classified open space; another 10 percent if it includes major recreation or leisure facilities like a clubhouse or swimming pool; and a 15 percent bonus if active or passive solar systems, or passive solar design, are incorporated into 50 percent of the dwelling units.

Those three criteria can stack, but the combined bonus is hard-capped at 30 percent regardless of how many criteria a project satisfies. 360. 320 before any of this density math applies.