This bill amends the statutory definition of "sale" in RCW 82.45.010, adds a new exemption section to chapter 84.36 RCW, and creates multiple limited real estate excise tax and property tax exemptions and related rules for transfers and ownership of affordable and social housing. The amended "sale" definition expressly includes transfers or acquisitions of a controlling interest in entities owning in-state real property within any 36-month period, requires aggregation of acquisitions by persons "acting in concert" with department rulemaking, and preserves numerous specific exclusions and a federal tax nonrecognition exclusion subject to a 36-month anti‑abuse limitation. The act also directs the housing finance commission and JLARC to collect data and review a low‑income housing tax preference in 2033. The bill establishes exemptions and procedural conditions for several transaction types: transfers of qualified low‑income housing developments; transfers by a legal representative of an adult with developmental disabilities to a "qualified entity" (limited to small residences, conveyed without consideration, and required to remain in use for supported living for 50 years); transfers to qualifying grantees (nonprofits, social housing agencies, public corporations, counties, municipalities, housing authorities) that use property for low‑income housing subject to recorded covenants, certification affidavits, and timelines to obtain property tax exemptions (operate existing housing within 1 year, substantially rehabilitate within 3 years, develop new housing within 5 years). If timeline or use requirements are not met the grantee must pay the tax that would have been due at transfer plus interest under RCW 82.32.050. The Department of Social and Health Services may determine placement safety for developmental‑disability residences and must notify "the department" if health and safety standards are not met, which triggers immediate excise tax due by the qualified entity (that tax is stated not to be subject to penalties, fees, or interest under this title). The bill also creates a new property tax exemption for social housing agencies that meet occupancy and financing conditions, includes rules for partial exemptions, and limits on incidental uses; it authorizes the department to require affidavits and access to books to confirm eligibility. The text available leaves some details incomplete or unspecified: the specific identity of "the department" referenced in multiple filing, notification, and rulemaking duties is not named in the extracted text, portions of subsection (3)(t) and subsection (3)(u) are cut off, and the full text of amendments to RCW 84.36.805 and other sections are not fully shown. The act also sets staggered effective and expiration dates for certain sections (Section 1 expires January 1, 2030; Section 2 takes effect January 1, 2030; Section 4 expires January 1, 2033; Section 5 takes effect January 1, 2033).

If enacted, the bill creates new and expanded property tax and real estate excise tax exemptions for rental housing owned or operated by social housing agencies and for transfers to qualifying nonprofits or public entities that will use property for low-income housing or supported living for people with developmental disabilities. Qualifying social housing agencies can get full or partial exemptions depending on the share of units occupied by households at or below 80% of area median income, with rules for vacant units, group homes, and financing sources; qualifying grantees must record covenants, file affidavits, and meet timelines (1, 3, or 5 years depending on the project) or face repayment of the tax that would have been due plus interest. Transfers from legal representatives of people with developmental disabilities can be exempt if the property has no more than four units, is conveyed without consideration, and is kept in supported living use for 50 years; DSHS can trigger immediate real estate excise tax if the property fails health and safety requirements. The parties most affected are social housing agencies, nonprofit developers, housing authorities, counties/municipalities that serve as qualifying grantees, and legal representatives transferring family homes; they will likely pay less property tax on qualifying properties but face new compliance tasks: recording covenants, submitting affidavits, meeting occupancy and timeline obligations, and potential recapture liability if conditions are not met. State agencies also gain new duties: DSHS must monitor safety and notify the tax department to collect excise tax when warranted, the housing finance commission must gather data for a JLARC review in 2033, and an unnamed “department” must adopt rules on aggregation of transfers and receive filings. The bill text leaves some implementation details unclear, including the identity of “the department” in several places and the full text of certain sections referenced here.