Phosphorus-Based Product Prohibitions & Limitations
Why the District is addressing phosphorus
Phosphorus is a nutrient that can contribute to algae growth in local waterways. To help protect water quality and manage treatment costs, the District adopted Phosphorus-Based Product Prohibitions and Limitations (2022), which limit phosphorus in cleaning products to 0.5% by weight.
Why it matters
The District’s $50M Water Resource Recovery Facility (WRRF) was designed to remove phosphorus from wastewater. However, higher phosphorus levels require more treatment chemicals, which:
- increases treatment costs
- increases the amount of biosolids generated
- can contribute to higher long-term operational costs for ratepayers
Typical phosphorus levels in wastewater are 5–8 mg/L, coming from human waste and common cleaning products. Levels observed in Big Sky’s wastewater have been higher (8–15 mg/L), which may indicate the use of cleaning products with higher-than-normal phosphorus concentrations.
What you can do
- Choose cleaning products labeled low- or no-phosphorus.
- Check labels for phosphorus ingredients like phosphoric acid and trisodium phosphate (TSP).
Small changes in product choice can make a big difference in protecting our watershed and reducing treatment costs.
Ordinance information
The full ordinance language can be found in Article 12 of the Wastewater Use Ordinance, District Ordinance 97-1001 (Amended March 28, 2023).