Preliminary Healthcare Cost Savings Results

In spring 2025, the Center received a McIntire-Stennis Cooperative Forestry Research award to begin assessing the cost savings of spending time in nature in Washington state. We’re excited to share our preliminary findings with the nature and health community.

As an initial step in this project, our team conducted what we believe is the first-ever estimate of green space-related healthcare cost savings specifically for Washington state. Using satellite-derived vegetation data (NDVI) from MODIS imagery and a benefit transfer methodology based on a landmark study of five million Kaiser Permanente members in Northern California, we estimated how per-capita healthcare costs vary across ten levels of residential greenness in Washington.

The results reveal a clear pattern: residents living in the least green neighborhoods face estimated annual healthcare costs of approximately $6,473 per person, compared to roughly $5,939 for those in the greenest areas, a difference of nearly $533 per person per year. Notably, the relationship is not linear: the cost savings associated with moving from moderate to high greenness levels are significantly larger than those associated with moving from low to moderate levels. This dose-response pattern suggests that as residential vegetation exposure increases, healthcare cost savings may accelerate.

Washington has higher greenness thresholds and a larger proportion of its population in the upper greenness deciles than Northern California, indicating that the state is generally greener. Because the Northern California model cannot project the impacts of these higher levels of greenness, the transferred estimates likely underestimate the cost savings attributable to green space in Washington. It is our hope that this initial estimate of the economic value of the health benefits of nature in Washington will help policymakers, healthcare insurers, and community planners make the case for green infrastructure as an important public health investment.

Explore the data

• 2020 Washington’s Normalized Difference Vegetation Index (NDVI) by Decile
• 2020 Washington’s Estimated Healthcare Cost per Capita by Decile