Petitioner, City of Happy Valley (Happy Valley), seeks judicial review of a determination by the Land Use Board of Appeals (LUBA) that its comprehensive plan violates Statewide Planning Goal 2, in that it fails to provide for a residential development density equal to that said to have been assumed in the establishment of Metropolitan Service District’s (Metro) Urban Growth Boundary (UGB).
In January, 1980, the Land Conservation and Development Commission (LCDC) acknowledged the Metro UGB as being in compliance with statewide planning goals. In the findings supporting adoption of the UGB, Metro apparently expressed an assumption that residential unit development inside the boundary would achieve an overall average density of somewhat over 6 units per net acre (UNA).1 Happy Valley is a constituent jurisdiction in the Metro region, and after Metro reviewed Happy Valley’s comprehensive plan, it wrote to Happy Valley in June, 1980, stating in relevant part:
“In summary, with the exception of a few small cities with limited potential for new housing development or redevelopment, jursidictions in the Metro area must accommodate at least a 50/50 SF/MF [single family/multifamily] new construction ratio unless otherwise justified and provide opportunities that moderate the cost of housing. Also, they must provide for an overall new construction density of at least 6 UNA depending on jurisdiction size, amount of buildable land and locational factors. For smaller cities with some growth potential, overall new construction densities of 6 UNA are minimally sufficient to meet Goal #10. For medium-sized cities and counties with lands generally bordered by rural land, local plans must provide for about 8 UNA. Larger jurisdictions must plan for about 10 UNA for new construction. In practical terms, this will mean average single family lot sizes of 6,000 to 8,000 square feet and multi-family densities of about 20 UNA.”
Previous communications from Metro to Happy Valley had emphasized that before Metro would recommend Happy *908Valley’s comprehensive plan for acknowledgment by LCDC, buildable land would have to be designated for at least 6 UNA.
Respondents own a total of approximately 150 acres of undeveloped land in Happy Valley, which they seek to develop. In the course of the comprehensive planning process before the city, respondents sought relatively high development densities for their properties. In August, 1980, Happy Valley adopted its comprehensive plan and implementing ordinances. Despite the previous communications from Metro, the comprehensive plan, as adopted, provided for an overall average residential density of only 2.46 UNA for new development; it allowed respondents to develop their land at a density no greater than 3 UNA.
In September, 1980, respondents challenged Happy Valley’s comprehensive plan before LUBA,2 alleging violations of Statewide Planning Goals 2, 3, 9, 10, 11, 12 and 14, and of Article I, section 20, of the Oregon Constitution. In its final order, LUBA characterized the attack on the validity of the comprehensive plan as being directed principally at the low average density figure of 2.46 UNA. LUBA resolved the matter by finding a prima facie inconsistency between the comprehensive plan and the regional plan, of which it considered the Metro UGB to be a part, under Goal 2.3 LUBA concluded:
“Happy Valley has not demonstrated that the land which is suitable for development cannot-support densities which would enable Happy Valley to meet the overall 6 units per net acre average. Happy Valley has not demonstrated any justification for deviation from the density *909standard contained in the Metro UGB. Accordingly, Happy Valley’s comprehensive plan violates Statewide Planning Goal 2.”
On appeal, Happy Valley contends that Metro’s assumption of an overall regional density in establishing the Metro UGB does not constitute a minimum density requirement binding on constituent local governments. It is worthwhile to scrutinize LUBA’s reasoning in finding such a standard:
“* * * As part of its review of the Metro UGB for acknowledgement, LCDC concluded Metro’s assumptions concerning overall density were not necessarily adequate to meet Goal 10 although they were adequate for meeting the purposes of Goal 14:
“ ‘Falling short of regional UGB housing guidelines may, in certain limited circumstances, be acceptable. However, merely zoning for these minimal regional densities and mix assumptions does not necessarily guarantee compliance with Goal 10. Generally speaking to comply with Goal 10 local zoning must provide for densities considerably in excess of UGB densities assumptions.’ Adopted DLCD acknowledgement of compliance report on Metro UGB, December 13, 1979.
“In its acknowledgement of the Metro UGB, LCDC conditioned acknowledgement upon Metro’s assurance that it would provide effective growth control mechanisms and upon Metro’s implied assurance that development within the Metro UGB would occur at least [at] an average overall density of 6 plus units per net acre and greater if and where necessary to meet regional housing needs. Thus, the Metro UGB not only delineates the area within which urban growth is to occur in the Metro region, it also sets forth an average density requirement which must be met by jurisdictions with planning and zoning responsibilities within the confines of the Metro UGB.” (Emphasis supplied.)
LUBA’s reasoning hinges upon the premise that the Metro UGB would not have been acknowledged were it not for an “implied assurance” that a minimum development density would be achieved inside the boundary. However, that premise is unsupported in the record; even if it were supported, it is highly doubtful that an “implied assurance” by Metro to LCDC, not explicitly contained in the Metro UGB, may be treated as a density standard which Metro constituent jurisdictions are required to *910follow in order to be consistent with the Metro UGB. From all that appears in this record, the Metro UGB does not itself purport to impose a minimum density standard for constituent jurisdictions.
Moreover, the quoted portion of LCDC’s Metro UGB acknowledgment report speaks only in terms of what is required for compliance with Goal 10 (housing).4 The report makes residential development density a substantive goal issue, not a matter of Goal 2 consistency. Whether Happy Valley’s comprehensive plan complies with Goal 10 was not reached by LUBA in its consideration of this case. The acknowledgment order itself does not contain an express minimum density requirement.5 Unlike LUBA, we do not interpret LCDC’s acknowledgment as establishing a prima facie minimum density standard.
We do not reach the question of whether Metro is authorized to make such a density requirement part of its urban growth boundary.6 We hold only that a regional average residential development assumption, which is only one of many factors considered in the formation of the Metro urban growth boundary, does not constitute a prima *911 facie density requirement for constituent jurisdictions for the purposes of Goal 2.7
. We reverse, because we find LUBA’s determination of a Goal 2 inconsistency between Happy Valley’s comprehensive plan and the Metro UGB to be “unlawful in substance,” Or Laws 1979, ch 772, § 6a(8)(a), and we remand to LUBA for consideration of respondents’ other contentions.
Reversed and remanded for further consideration.