The manual provides guidelines for the cost estimator concerned with various wastewater treatment systems. Direction is given for the uniform presentation of capital and annual cost data now being developed. Individual sections deal with suggested forms for submitting reports, including an outline, and method and format for preparing capital and annual cost estimates for Federal Water Quality Administration (FWQA) studies. The following specific data are appended: Summary of cost indices useful in scaling capital costs of previous years to present; Description of typical operating cost data; sources of additional data; Discussion of municipal bonds and financing; Discussion of levels of estimates and expected accuracies.