Analytical Services



The Clean Water Act (CWA) arose from significant amendments to the Federal Water Pollution Control Act of 1948. Due to increased concern for the quality of surface waters and the need to control pollutants from contaminating water systems the amendments enacted in 1972 became the law that is commonly known as the Clean Water Act. The CWA constitutes the primary means for regulating point source pollution and establishes the mechanism for the NPDES permit program. The EPA National Pollutant Discharge Elimination System (NPDES) permit program is designed to control discharge of contaminants into waters of the United States. The 1972 amendments:

  • Establish regulations for controlling the introduction of pollutants into navigable waters.
  • Provide authority to the Environmental Protection Agency (EPA) to implement programs and set standards for both wastewater and surface water.
  • Establish a permit program for discharging into defined water systems and enact laws governing discharges.
  • Fund construction of sewage treatment facilities.
  • Address planning needs for nonpoint source contamination.

Clean Water Act amendments enacted in 1981 revised the municipal construction grants program and in 1987 changes to the CWA replaced the construction grants program with the State Water Pollution Control Revolving Fund (currently the Clean Water State Revolving Fund). Further programs governing water quality in the Great Lakes and other laws have resulted in changes to the CWA.

Pollutants, waters of the United States and point sources are broadly defined in the CWA and have undergone extensive litigation in the eventual evolution of the definitions for these terms.

The goals of the CWA are to:

  • Protect the Nation’s waterways
  • Establish and maintain water quality standards
  • Control the release of contaminants into surface water
  • Develop technologies to treat waste water
  • Partner with States and municipalities to achieve the desired reduction in pollution discharge

NPDES Permitting

The discharge of pollutants into navigable waters from point sources without a permit is prohibited under the CWA. The control of discharges is regulated by the NPDES permit program. EPA is the primary responsible agency for administering the NPDES permit program. States, tribal and territorial governments may receive authorization from EPA to perform many of the permitting, administrative and enforcement functions with EPA retaining oversight.

Facilities that will be discharging materials into surface water systems are required to apply for a NPDES permit. The permit will be specific for the individual facility. The permitting authority will generate a distinct permit that will specify the type of facility, nature of the discharge, the receiving water and the amount of pollutant that can be discharged. NPDES permits will include effluent limits that are based on consideration of both technology-based effluent limits (TBELs) and water quality-based effluent limits (WQBELs).

Technology-based effluent limits will specify minimum treatment procedures for controlling the amount pollutant that will be discharged. Water quality-based effluents limits will be designed to identify an amount of pollutant that can be discharged into the receiving water and continue to maintain established water quality standards. Facilities are required by their permit to sample and test effluent discharges and provide the permitting authority with the results. Actions must be taken when testing results demonstrate that regulated pollutants discharged exceed the allowable limit specified in the permit.

Compliance with the provisions of the permit will be monitored and non-compliance may result in orders issued for corrective actions, assessment of fines and civil or criminal legal actions. Permits are issued for a defined time period (up to five years) and must be renewed prior to expiration.

National Pretreatment Program

One of the components of the NPDES program included the ability of municipalities that operate publicly owned treatment works (POTWs) to perform permitting, administration and enforcement activities for discharges into the POTW. The goals of the National Pretreatment Program are:

  • To ensure proper operation of the POTW in order to maintain compliance with its permit.
  • Protect the POTW treatment facility
  • Reduce the amount of potential industrial pollutants discharged into municipal sewer systems and ultimately the environment
  • Provide the POTW with monitoring and enforcement to ensure discharges can be controlled and water quality standards maintained

Industries that discharge waste streams into municipal sewer systems must obtain a permit from the municipal POTW and are required to monitor effluents to maintain compliance with the permit. Facilities will be required to sample and test effluents and remain in compliance with the discharge amounts of specific pollutants designated in their permit. The permit will specify the frequency and parameters that must be sampled and tested for compliance. The facility must provide the municipal authority with reports of the monitoring and take actions when exceeding discharge limits.

Testing Procedures

Determination of compliance with permit limits and effluent discharge of specific pollutant parameters requires analysis of the discharge water using approved analytical methods. Approved procedures for testing waste water are listed in 40 CFR Part 136. Guidelines for sampling including the type of approved containers and holding time for analytical methods are specified in the CFR. In addition the approved testing methods for individual constituents are listed. Analytical methods are based on testing procedures that have been developed and validated by various agencies. Reference methods are available from the following sources

  • EPA
  • Standard Methods
  • ASTM
  • AOAC
  • USGS
  • Other as approved by EPA

Methods have undergone revision over the years and some methods have been withdrawn and substituted with update methods from other agencies. Many of the original methods published by EPA have been replaced due to lack of updating by more current methods. Several changes to the CFR through Method Update Rules (MUR) have revised the list of approved methods for testing individual constituents. Standard Methods for the Examination of Water and Wastewater have replaced many of the former EPA reference methods. In addition methods developed by ASTM, AOAC and USGS have provided viable options for testing.

Methods other than listed in the CFR or modifications to the reference method can be accepted for testing provided the laboratory obtains approval for an Alternative Test Procedure (ATP). The modification to the method or the laboratory developed method is submitted to the permitting authority and reviewed by both the permitting authority and the regional EPA office. If the method or modification is deemed acceptable the laboratory receives an ATP for the procedure and may analyze samples under the ATP.

Method updates have caused difficulties for permit holders. Methods that are cited on a facility permit may have been withdrawn and replaced prior to the permit expiration causing confusion for the laboratory servicing the permittee and the facility. Coordination with the permitting authority and the laboratory is essential in ensuring the proper method is used for testing

Laboratories performing testing for wastewater discharges are expected to maintain quality standards that ensure the accuracy of the test results. Some States have required testing laboratories to be accredited either by the State accrediting body (AB) or an independent accreditation program. Many States have adopted the National Environmental Laboratory Accreditation Program (NELAP) as currently administered by The NELAC Institute (TNI). Accreditation program provide standard policies for laboratories that assist in ensuring that the testing laboratory maintains the requisite quality standards for their respective analytical activities.

DMRQA – Discharge Monitoring Report-Quality Assurance

In order to assess the ability of testing laboratories to perform reliable analysis of discharge effluents EPA developed the DMRAQA proficiency testing (PT) program. The DMRQA PT program was designed to monitor the capability of laboratories to generate acceptable data for the requirements of the NPDES program. Testing of effluent water whether by laboratories associated directly with the permit holder or sub-contracted by the facility for effluent testing required participation in the DMRQA program. This program applied to facilities maintaining a NPDES permit and was not required for reporting to industrial or other facilities discharging to a POTW.

Initially PT samples were provided by EPA directly. Subsequently EPA ceased this service and the DMRQA program was administered by independent PT providers authorized to provide and evaluate the samples. PT samples were formulated by the provider to contain specific concentrations of the analytes of interest that were unknown to the participating laboratories. The laboratory was required to analyze the samples according to the procedures being used for water testing and supply the results to the PT provider. The PT provider would evaluate the laboratory data with respect to the expected result and the acceptance range established. Reports of the study results would be forwarded to the participating laboratories. The laboratory would then submit the results with the evaluation to the respective permittee that would then provide the data to the permitting authority. Results that exceeded the acceptable limits required the laboratory to take corrective actions to identify the cause of the unacceptable result and formulate a plan to correct the problem.

RTI Testing Capabilities

RTI maintains full testing capabilities in support of the CWA and NPDES program and annually participates in the DMRQA study. RTI performs testing for both NPDES permit holders and industries discharging to a POTW. RTI performs analyses according to the procedures specified in the CFR and has successfully applied for and received ATPs when required. The laboratory has instrumentation and procedures that have undergone method validation process and are capable of meeting the guidelines in the reference methods. RTI has processed samples through the extraction and analytical procedures, performed demonstration of method performance, determined method detection limits, established quantification limits, assessed the accuracy and precision of the procedures and have developed standard operating procedures for the analysis of water and wastewater samples.