Individual Lagoon Tool for Supporting Ammonia WQS Variances

The Individual Lagoon Tool (ILT) is a screening-level economic analysis tool to help determine whether a water quality standards (WQS) variance for ammonia based on “substantial and widespread economic and social impacts” (i.e., 40 CFR 131.10(g)(6) or “Factor 6”) may be appropriate. This tool is specific to lagoon wastewater treatment systems with design flow between 0.01 and 2 million gallons per day (MGD).

The tool combines a preliminary analysis of the engineering costs for installing lagoon replacements or modifications that could provide adequate treatment to allow the lagoon wastewater treatment system to meet the applicable ammonia criterion along with the socioeconomic analyses described in the following:

• 1995 Interim Economic Guidance for Water Quality Standards: Workbook (pdf) (2.29 MB, March 1995, EPA-823-B-95-002)
• Clean Water Act Financial Capability Assessment Guidance (2024 Revision) (pdf) (1.19 MB)  ("FCA Guidance")

Socioeconomic analyses recommended in the guidance documents above inform whether a community will likely incur substantial economic and social impacts. These analyses include the Municipal Preliminary Screener (MPS), the Secondary Test, the Lowest Quintile Poverty Indicator (LQPI) Score, and a Financial Alternatives Analysis (FAA).

This tool is applicable to lagoon wastewater treatment systems within the 50 U.S. states, District of Columbia, and Puerto Rico, including Tribal lands within those locations. Communities on Tribal lands should work with their EPA Regional Contact to potentially identify economic data that may better characterize the community than data available in the Individual Lagoon Tool. Additionally, communities in the U.S. Virgin Islands, Northern Mariana Islands, Guam, and American Samoa should work with their EPA Regional Contact to develop an appropriate analysis, rather than use this tool, because U.S. Census data and engineering cost data are not available for those territories.

On this page:

1. How to Use This Tool
2. Use This Tool
3. Location
4. Existing Pollution Control
5. Proposed Pollution Control
6. Municipal Preliminary Screener
7. Secondary Test
8. Lowest Quintile Poverty Indicators
9. Summary of Tool Outputs
10. Next Steps

How to Use This Tool

1. Select the state where the community is located and then select the Type of Jurisdiction (i.e., county, city/town, or zip code) and the corresponding location that best represents the lagoon's service area. Demographic and economic data for that location will then be automatically retrieved from the US Census American Community Survey (the Census).
2. Review the retrieved Census data. If you have more accurate data, click the check box labeled alternate value for the relevant field and enter the more accurate data. Please include the data's source in the accompanying explanation field.
3. Enter data into the Existing Pollution Control, Proposed Pollution Control, and Secondary Test sections. Fields with default values are marked with the letter “d”. If you have more appropriate data for your community, please overwrite any default value.
   1. Required data with no defaults include an estimate of existing pollution control costs (e.g., average monthly sewer bill) and the design flow of the lagoon.
   2. Required data with defaults available include the type of lagoon system, influent temperatures, estimated loan duration and interest rate to finance the proposed pollution control project, grant funding, and the percentage of pollution control costs borne by households. Use community-specific data when available to increase the accuracy and utility of the analysis.
   3. Highly encouraged, optional data include community economic data such as debt and property tax information. Use these data to increase the accuracy and utility of the analysis.
4. In the Results section, indicate whether a Financial Alternatives Analysis was performed.
5. In the Data and Information Download section, you can copy and paste a summary report into your document.

Your web browser will automatically save the data you enter even if you close the browser. When you return to the tool using the same browser and computer, it will prompt you to either restore the previous data or clear it. (Note: Data stored by the tool reside only on your local computer and are not transmitted to EPA or anywhere else. All data are lost when cleared within your browser).

Symbols

• d - Data entries for these input fields have default values that may be used if information specific to the community cannot be located. Use community-specific data when available to increase the accuracy and utility of the analysis.
• i - Click for additional information and instructions regarding the data that should be entered for the field.

Financial Alternatives Analysis

The FCA Guidance recommends performing a Financial Alternatives Analysis (FAA). As noted in the FCA Guidance, an FAA, especially when performed at the beginning of an economic impact analysis for WQS decisions, may help provide the community with a clearer understanding of all costs associated with the implementation of Clean Water Act controls, such as reduced costs associated with low-interest loans, increased revenue from utility fees, or the costs associated with programs that assist low-income households. The ILT inputs that may change based on the results of an FAA include existing pollution control costs, proposed pollution control costs, and secondary test indicators. Including the economic effects of viable financial alternatives will strengthen the demonstration of substantial and widespread economic and social impacts.

The ILT may not capture the economic impacts of some financial alternatives such as those from variable rate structures or customer assistance programs. In that case, you should consider the results of the ILT and the FAA together to evaluate whether economic and social impacts are substantial, as recommended in the FCA Guidance.

Other Important Information

Use of this tool and resulting outputs does not guarantee EPA approval of a WQS variance. This tool does not impose legally binding requirements on the United States Environmental Protection Agency, states, territories, authorized Tribes, or the regulated community, nor does it confer legal rights or impose legal obligations upon any member of the public. The Clean Water Act provisions and EPA regulations implemented by this tool contain legally binding requirements. This tool does not constitute a regulation, nor does it change or substitute for any Clean Water Act provision or EPA regulation. This tool may be revised periodically without public notice. The adoption of a WQS variance is at the discretion of the state, territory, or authorized Tribe. The EPA encourages early and frequent coordination between a state, territory, or authorized tribe and the EPA Region before adopting a WQS variance to provide the best chance that it meets the requirements of the Clean Water Act and its implementing regulations.

Tool Update Year: Cost estimates for proposed pollution control projects and Census economic data are for yr dollars except for Census data associated with zip-code locations. Data associated with Census zip-code locations are for yr because the Census Bureau does not yet provide these data for years after yr.

For any questions on this tool, please contact EPA Office of Water, Office of Science and Technology, Standards and Health Protection Division at (202) 566-1018.