A Water-Secure Future, One Building at a Time
Globally, our cities face a water-scarce future with rapid urbanization and economic growth along with climate change impacting water availability and quality. Reducing water usage in buildings is one step towards a water-secure future.
Under current climate conditions, 44% of our large cities face High to Very high-water stress. In one study of 71 cities with more than 750,000 inhabitants, it was estimated that 35% of the cities are presently vulnerable to water shortages. Towards mid-century, water stress will likely become more severe with a 24% increase in the number of large cities experiencing Very high-water stress.
Buildings are large water users
In one study, the US EIA estimated that 46,000 large commercial buildings (greater than 200,000 square feet) used nearly 360 billion gallons of water in one year, equivalent to around 2.3% of the total public water supply in the United States. On average, these buildings used 7.9 billion gallons per building, 20 gallons per square foot, and 18,400 gallons per worker.
The City of Boston’s buildings saving water (and energy)
The City of Boston’s Building Energy Reporting and Disclosure Ordinance (BERDO) requires Boston’s large- and medium-sized buildings to report their annual energy and water use. It also requires buildings to complete a major energy savings action or energy assessment every five years. In 2020, BERDO requires the following portfolios to report their annual energy and water usage for the 2019 calendar year:
- Non-residential buildings that are 35,000 square feet or larger
- Residential buildings that are 35,000 square feet or larger or have 35 or more units
- Any parcel with multiple buildings that sum to 100,000 square feet or 100 units
To enhance transparency, the City of Boston allows the public to search the publicly disclosed energy and water database. This helps property owners and interested stakeholders to understand how a buildings’ performance compares with similar buildings nationally. They also learn, after public disclosure, how the building compares with other Boston buildings. Furthermore, the City of Boston provides an online map that shows the energy and water metrics for all reporting buildings across Boston.
Conclusion
By saving water and energy at the building-level, cities can enhance their resilience to future climatic extremes.