HDD High-Density Development Any housing development over the number of 25 dwelling units per acre (DU/acre) in Huntington Beach, California, is considered HDD (may vary in other cities). By Nils Admin Nehrenheim|2026-02-26T02:09:56-08:00February 26, 2026|Glossary, Housing & Development Acronyms & Terms|Comments Off on HDD Share your Voice, Share Our Voice! FacebookX About the Author: Nils Admin Nehrenheim