Evelyn Costa Elementary, Mountain House CA

Original Research by School Decision on Evelyn Costa Elementary

Evelyn Costa Elementary is a K-8 school opened in mid-2023 as part of Lammersville Unified, serving a rapidly growing master-planned residential community in Mountain House in San Joaquin County. The school sits at the neighborhood center of the community's southern villages, anchoring one of several walkable K-8 zones that define Mountain House's structure. The enrollment is small to mid-sized for a K-8, with kindergarten as the largest grade and eighth grade the smallest, reflecting the school's newness and the community's still-unfolding development.

The student body is predominantly Asian, with small representations across other racial and ethnic groups. Only a very small share of students qualify for free or reduced-price lunch, which broadly aligns with Mountain House's profile as a master-planned community of mostly owner-occupied new-build homes whose residents tend toward higher income. The school's enrollment data for English learners and students with disabilities was not made available.

On California's 2024-25 state tests, Evelyn Costa shows uneven performance across grade levels and subjects. In math, grades three through five and grade seven sit solidly in the proficient range, while grades six and eight fall below that threshold. English language arts tells a different story: third grade sits noticeably lower, but fourth through eighth grades reach proficiency, with seventh grade performing exceptionally well. Science results, available only for grades five and eight, show grade five in the lower-proficiency range and grade eight substantially higher. Across all tested grades and subjects combined, the school sits above the midpoint for proficiency among San Joaquin County's school-level test takers, placing it in the top quartile of the county's tested schools. This is a meaningful signal but warrants context: the school is newly open, serving a demographically distinct student population in a specific community subset, so comparisons to longer-established schools and different populations carry some grain of salt.

No prior-year data is available to assess growth or trajectory. As a brand-new school, trends are not yet established. Parents may want to reach out to the school directly about recent enrollment patterns, retention, and the school's early implementation priorities.

Mountain House itself is an overwhelmingly residential master-planned community of new-build homes organized into distinct neighborhoods, each built around a K-8 school and neighborhood parks. Most residents own their homes and commute outward to the Bay Area or Sacramento for work; the local job base remains limited and leans toward logistics and retail. Commercial amenities have lagged behind housing, though that is gradually changing. The community is notably diverse, walkable at the neighborhood scale, and oriented toward family life and schools. Housing values in the area are substantial; the cost of a new home and monthly mortgage payments are well above national and state medians, though notably most residents own outright rather than carrying mortgages, and the ownership model generally means lower turnover and stability for schools.

The Lammersville district recently completed a Phase III expansion at Mountain House High School, adding classrooms and science labs and supporting a seven-period day that lets a portion of students take an additional course. This is relevant for families planning a full K-12 pathway in the community. Evelyn Costa itself is that same district's newest school, so the district is actively expanding to serve community growth.

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Academic performance

How students perform on state tests, by grade, set against the district.

Math

Grade 379%

School 79% · District 74% · ▲ 4 pts above district

▲ 36 pts above state median · ▲ 48 pts above county median

Grade 480%

School 80% · District 73% · ▲ 7 pts above district

▲ 43 pts above state median · ▲ 54 pts above county median

Grade 581%

School 81% · District 70% · ▲ 11 pts above district

▲ 51 pts above state median · ▲ 61 pts above county median

Grade 675%

School 75% · District 73% · ▲ 2 pts above district

▲ 45 pts above state median · ▲ 53 pts above county median

Grade 786%

School 86% · District 72% · ▲ 14 pts above district

▲ 56 pts above state median · ▲ 64 pts above county median

Grade 875%

School 75% · District 74% · ▲ 1 pts above district

▲ 47 pts above state median · ▲ 53 pts above county median

English language arts

Grade 365%

School 65% · District 67% · ▼ 1 pts below district

▲ 25 pts above state median · ▲ 35 pts above county median

Grade 478%

School 78% · District 72% · ▲ 6 pts above district

▲ 36 pts above state median · ▲ 48 pts above county median

Grade 583%

School 83% · District 75% · ▲ 8 pts above district

▲ 38 pts above state median · ▲ 50 pts above county median

Grade 678%

School 78% · District 77% · ▲ 1 pts above district

▲ 34 pts above state median · ▲ 45 pts above county median

Grade 794%

School 94% · District 78% · ▲ 16 pts above district

▲ 48 pts above state median · ▲ 57 pts above county median

Grade 884%

School 84% · District 80% · ▲ 5 pts above district

▲ 40 pts above state median · ▲ 46 pts above county median

Science

Grade 563%

School 63% · District 61% · ▲ 2 pts above district

▲ 35 pts above state median · ▲ 45 pts above county median

Grade 878%

School 78% · District 73% · ▲ 5 pts above district

▲ 52 pts above state median · ▲ 59 pts above county median

This schoolLammersville Joint Unified, same grade

Graduation rate (ACGR) reflects the federally published Adjusted Cohort Graduation Rate for the most recent year available. We refresh this data annually at the close of each academic year in June. The federal source publishes a banded rate (for example, "90-94%") instead of an exact number for cohorts small enough to risk identifying individual students. The state distribution chart, where shown, plots every school in the state with a published rate or band; schools whose rate is federally suppressed are excluded. Where the federal source publishes a band rather than an exact rate, the school is placed within its band using a stable, ID-derived offset, so its position is consistent across visits.