Climate Change + Population Increase = Imbalance in the Waterways of Cape Cod, Massachusetts. The old septic systems used by about 95% of the growing population of Cape Cod are contributing to rising nitrogen and phosphorus levels in the waterways which are slowly warming due to climate change. Septic systems are a great option in places where homes are too spread out to justify sewers and water treatment plants but they don’t filter out the nitrogen and phosphorus that ends up seeping into groundwater. When nutrients like nitrogen and phosphorus runoff into the water, they act as a fertilizer for bacteria and algae. This combination of factors has resulted in an “explosion” of blue-green algae to take over the Cape and wreak havoc on the ecosystem. After several lawsuits filed by environmentalists, the state of Massachusetts has proposed that local communities are required to fix the problem within 20 years. This has created some pushback from the community of Mashpee, MA that has already started installing a sewer system, the construction of which was projected to be spread out over 25 years. If the proposed rule is enforced, that would force the community to move faster and find a way to cover the huge cost of construction. This raises the issue of cost in general since sewers and water treatment plants are extremely expensive for the community and new septic systems can be a huge expense to the individual homeowners in the area, many of whom are retired and living on fixed incomes. How this plays out in Massachusetts will be viewed by other states in the future as they seek to address similar surface water quality issues in areas with a high density of decentralized wastewater treatment. For more information concerning Nutrient Runoff from Septic Systems check out some of the following resources: Septic Systems and Surface Water This interactive graphic and diagram explains how nutrients and pathogens from your septic system may impact streams, lakes, or other water bodies near your home. Nutrients from septic systems can impact well and surface water This article goes into detail about the impact a malfunctioning septic system has on the surrounding waterways, wells, and groundwater. How Nitrogen from Septic Systems Can Harm Water Quality This 2-page fact sheet describes how nitrogen can affect the soil and water in the areas surrounding your septic system. For more information concerning Harmful Algal Blooms (HABs) check out some of the following resources from WaterOperator.org : Addressing HABs and Cyanotoxins in Drinking Water with the Drinking Water State Revolving Fund This 4-page fact sheet describes DWSRF eligibilities related HABS. It provides several case studies where DWSRF funds were used for HABs related activities. Algae/Cyanobacteria Toxins and Public Water Systems This 31-slide presentation discusses how to understand the problem, know what tools are available, and plan how to manage a cyanotoxin event. Algal Toxin Risk Assessment and Management Strategic Plan for Drinking Water This 81-page report is a strategic plan for assessing and managing risks associated with algal toxins in drinking water provided by public water systems. This plan presents examples of recently completed and ongoing HAB-related activities and provides steps and timelines for intended future EPA activities. These ongoing and future activities outline EPA’s plan for the next few months through the next five years and beyond.