At a glance
Waterworks Office & Marina is a 30,840-square-foot office building at 1818 WESTLAKE AVE N in Seattle, Washington, built in 1965. In its 2025 Seattle benchmarking disclosure it reported an ENERGY STAR score of 17 out of 100 (grade D) and a site energy-use intensity of 140.0 kBtu/ft². That score is higher than 3% of the 378 scored office buildings in Seattle.
Seattle Energy Benchmarking Ordinance (SMC 22.920) · reporting year 2025
Benchmarking record
| Field | Value |
|---|---|
| ENERGY STAR score | 17 (band D) |
| Site EUI | 140.0 kBtu/ft² |
| Source EUI | 254.0 kBtu/ft² |
| GHG emissions | — |
| GHG intensity | — |
| Electricity | 552,831 kWh |
| Natural gas | 24,300 therms |
| Gross floor area | 30,840 sq ft |
| Source record | seattle:25464:2025 |
The disclosure history
Year over year
| Year | Score | Δ | Site EUI | GHG emissions |
|---|---|---|---|---|
| 2025latest | 17 | +5 | 140.0 kBtu/ft² | — |
| 2024 | 12 | -2 | 144.8 kBtu/ft² | 136 tCO₂e |
| 2023 | 14 | +1 | 145.0 kBtu/ft² | 140 tCO₂e |
| 2022 | 13 | -5 | 140.6 kBtu/ft² | 125 tCO₂e |
| 2021 | 18 | +2 | 128.9 kBtu/ft² | 110 tCO₂e |
| 2020 | 16 | -6 | 141.9 kBtu/ft² | 126 tCO₂e |
| 2019 | 22 | -20 | 122.6 kBtu/ft² | 100 tCO₂e |
| 2018 | 42 | +18 | 93.8 kBtu/ft² | 78 tCO₂e |
| 2017 | 24 | -6 | 134.6 kBtu/ft² | 122 tCO₂e |
| 2016 | 30 | -5 | 116.4 kBtu/ft² | 99 tCO₂e |
| 2015 | 35 | 112.4 kBtu/ft² | 99 tCO₂e |
Compliance context
Seattle Energy Benchmarking Ordinance (SMC 22.920)
Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
Ownership
No owning organisation shown. Names of private individuals in the disclosure are not published here.
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Location
- Address
- 1818 WESTLAKE AVE N
- City
- Seattle
- State
- Washington
- ZIP
- 98109
- Coordinates
- 47.63538, -122.33980
Within ~1 km
Nearby benchmarked buildings
- Dexter Station Officescore 83
Office · 513,816 sq ft
- One Lakefront At 1287score 98
Multifamily Housing · 395,317 sq ft
- Westlake Steps & Marina Sluscore 99
Multifamily Housing · 393,641 sq ft
- West Lake Union Centerscore 90
Office · 381,511 sq ft
- Neptune Apartmentsscore 96
Multifamily Housing · 373,664 sq ft
- Leeward Aptsscore 95
Multifamily Housing · 358,944 sq ft
See also: most efficient in Seattle · biggest emitters
How does Waterworks Office & Marina compare with other office buildings in Seattle?
The latest disclosures cover 497 office buildings in Seattle, out of 3,871 buildings citywide. Waterworks Office & Marina's ENERGY STAR score of 17 compares with an average of 76 across the 378 that report a score; it scores higher than 3% of them and lower than 97%. Its site EUI of 140.0 kBtu/ft² is about 213% above the average of 44.8 kBtu/ft² — it uses more energy per square foot than the typical building in that group.
At 30,840 sq ft, it is about 84% below the average floor area of 196,452 sq ft for those buildings. Its 1965 construction date is close to the group's average year built (1965). Across all 24 jurisdictions BuildingCensus covers, the 15,264 office buildings average an ENERGY STAR score of 73 and a site EUI of 59.3 kBtu/ft².
How has Waterworks Office & Marina's energy performance changed over time?
BuildingCensus holds 11 Seattle disclosures for Waterworks Office & Marina, covering report years 2015–2025. Its ENERGY STAR score went from 35 in 2015 to 17 in 2025 (-18 points); its best year on file was 2018, at 42. Site EUI moved from 112.4 kBtu/ft² (2015) to 140.0 kBtu/ft² (2025), an 25% increase. Reported emissions went from 99 tCO₂e to 136 tCO₂e over the same span (up 38%).
What does an ENERGY STAR score of 17 mean?
ENERGY STAR scores run from 1 to 100 and are computed by the EPA's Portfolio Manager as a percentile against similar buildings nationwide, adjusted for climate, size and use: a score of 17 means the building performs better than about 17% of its national peers. BuildingCensus bands the score into report-card grades; 17 falls in band D — lowest band (1–54). It sits 58 points below 75, the threshold for ENERGY STAR certification. In Seattle, 69% of scored buildings are at 75 or above.
Site energy-use intensity (EUI) is the energy a building uses on site in a year divided by its floor area, in thousand Btu per square foot — lower is more efficient. Waterworks Office & Marina's 140.0 kBtu/ft² across 30,840 sq ft works out to about 4.3 billion Btu (1,265 MWh-equivalent) in 2025. Its source EUI of 254.0 kBtu/ft² also counts the energy lost generating and delivering that power, which is why it is higher. The disclosure also reports 552,831 kWh of electricity and 24,300 therms of natural gas for the year.
Which law requires Waterworks Office & Marina to report its energy use?
Waterworks Office & Marina reports under the Seattle Energy Benchmarking Ordinance (SMC 22.920), the legal basis of Seattle's Building Energy Benchmarking program, which publishes each covered building's annual benchmarking results. The record shown here is the report-year 2025 disclosure (source record seattle:25464:2025). Seattle's Building Emissions Performance Standard (adopted 2023) applies to buildings over 20,000 sq ft: benchmarking verification is due 2027–2030 and initial emissions targets 2031–2035, reaching net zero by 2041–2050, with fines for non-compliance.
More office buildings in Seattle
- Ballou Wright Building· 30,720 sq ft · EUI 29.0 kBtu/ft²
- Apex Belltown Condominium· 30,700 sq ft · EUI 29.3 kBtu/ft²
- FOURTH & UNION BUILDING/MEN'S WAREHOUSE· 30,525 sq ft
- Office Bldg, 4209 21ST AVE W· 30,172 sq ft · score 92 (A)
- Office Building With Caretaker Unit· 30,152 sq ft · score 95 (A)
- Mchugh Bldg· 30,109 sq ft · score 50 (D)
- Office buildings in Seattle· 497 benchmarked
- All Seattle benchmarked buildings· Seattle Energy Benchmarking Ordinance (SMC 22.920)
- Most efficient large buildings in Seattle
- Least efficient large buildings in Seattle
- Biggest emitters in Seattle
Frequently asked questions
What is Waterworks Office & Marina's energy grade?
Waterworks Office & Marina scores 17 out of 100 on ENERGY STAR — band D, lowest band (1–54) — in its 2025 Seattle disclosure. Scores are national percentiles against similar buildings; 75+ qualifies for ENERGY STAR certification.
How much energy does Waterworks Office & Marina use?
Its 2025 site energy-use intensity was 140.0 kBtu/ft² (254.0 kBtu/ft² source) across 30,840 sq ft, including 552,831 kWh of electricity and 24,300 therms of natural gas.
What are Waterworks Office & Marina's carbon emissions?
No greenhouse-gas emissions figure was reported for 2025.
Where is Waterworks Office & Marina?
Waterworks Office & Marina is at 1818 WESTLAKE AVE N, in Seattle, Washington 98109. Its coordinates are 47.63538, -122.33980 (latitude, longitude), as published in the Building Energy Benchmarking file.
How big is Waterworks Office & Marina and when was it built?
Waterworks Office & Marina has 30,840 sq ft of gross floor area, as reported in its 2025 disclosure. The disclosure lists 1965 as its year built. It is classed as office.
Is Waterworks Office & Marina covered by the Seattle Energy Benchmarking Ordinance (SMC 22.920)?
Yes — it appears in the 2025 Building Energy Benchmarking disclosure, which lists the buildings reporting under the Seattle Energy Benchmarking Ordinance (SMC 22.920).
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About this data
Source: Building Energy Benchmarking (Seattle Energy Benchmarking Ordinance (SMC 22.920)), as published October 2, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: BuildingCensus, “Waterworks Office & Marina, Seattle, Washington — 2025 benchmarking disclosure”, https://buildingcensus.com/buildings/seattle/waterworks-office-marina-5188501e (data as of October 2, 2026).