Laboratory Testing: Certification and Sampling Protocols

May 25, 2021

Laboratory Testing: Certification and Sampling Protocols

About the author:

Robert Ramnarine joined the National Testing Laboratories network in May of 1999 as quality assurance officer at Broward Testing Laboratory facility, in Fort Lauderdale, Fla. Robert received MS from Florida Atlantic University. Marianne R. Metzger is general products business unit manager of National Testing Laboratories, Ltd., Cleveland, Ohio. Ramnarine can be reached at rramnarine@ Metzger can be reached at 800.458.3330, ext. 223, or by e-mail at [email protected].


Probably the most common question laboratories get asked is “Is Your Laboratory EPA Certified?” There are many different types of certification based upon the type of laboratory. For example, wastewater laboratories are certified to meet the requirements of the Clean Water Act, whereas drinking water laboratories must maintain certification to meet the Safe Drinking Water Act. This article will focus on drinking water laboratories. In most cases the EPA generally does not directly certify laboratories, they have assigned this responsibility to states that have primacy. The EPA directly certifies laboratories under the Information Collection Requirements Rule to perform compliance monitoring because this is a rule that is directly implemented by the EPA. States must apply to the EPA to receive primacy under the Public Water System Supervision Program, which includes laboratory certification in addition to the numerous regulations designed to enforce the Safe Drinking Water Act. To obtain primacy, states need to show the EPA they will adopt standards that are at least as stringent as the EPA’s, and be able to enforce the regulations within their own jurisdiction. The only territories that do not have primacy are Wyoming and the District of Columbia, which are regulated directly by the EPA.

Obtaining State Certification

There are a few options for obtaining state certification: direct certification; reciprocal certification; and National Environmental Laboratories Accreditation Program (NELAP). In the case of direct certification, the lab applies directly to the state agency that overseas the certification program. Direct certification typically requires the laboratory to submit an application that would include the following: legal name of the laboratory; laboratory location information; laboratory personnel qualifications including education and experience, type of analysis and methodology for which they are seeking certification; and quality assurance plans. In addition to the application, laboratories must submit Performance Evaluation (PE) studies for the analytes they are applying for certification to run. The laboratory must purchase PE samples from a state-approved vendor for the analytes they are seeking certification. These PE samples have a known concentration of the analyte, so the laboratory must analyze and report the results to the state agency. The EPA and/or state have specified ranges for each analyte or method in which the laboratory’s reported result must fall in order to pass. Depending on the state’s requirements, the lab must pass one or two of these PE studies. Many states require an on-site audit of the laboratory, where they send auditors to the laboratory to inspect and verify the laboratory is following all applicable procedures. The state will determine how often the laboratory must be audited in order to maintain accreditation. Lastly, the laboratory must pay all the applicable fees, which may include travel expenses for the on-site audits. Reciprocal certification is not always an option, but certain states will accept another state’s certification in lieu of directly certifying the laboratory.

Reciprocal certification has it’s advantages and disadvantages. The biggest advantage is in terms of cost of onsite audits. If a state accepts another state’s certification, they rely on the original state’s audit. A disadvantage is that the list of analytes the secondary state will certify for is based solely on the primary state’s list. This presents a problem when the primary state does not certify for everything the secondary state does, so the laboratory may end up with missing certification in the secondary state for some analytes.

NELAC Standards

National Environmental Laboratory Accreditation Conference (NELAC) is a cooperative association of state and federal agencies that was formed to establish and promote performance criteria for environmental laboratories. NELAP is the program, which implements the NELAC standards. Laboratories seeking NELAC certification must apply in their home state if it is one of the 11 states that are participating in NELAC. The states participating include: California, Florida, Illinois, Kansas, Louisiana, New Hampshire, New Jersey, New York, Oregon, Pennsylvania and Utah. If the laboratory is not located in one of the NELAC states, they can apply for NELAC accreditation through one of the above-mentioned states. NELAP accreditation is much like the direct state certification in that it requires a similar application which includes: a demonstration of the qualification of the laboratory personnel; laboratories are required to pass two consecutive PE studies; and an on-site inspection once every two years.

The objective of NELAC is to make rules and regulations for laboratory certification uniform, so laboratories are not trying to meet 50 different requirements from the individual states. Once NELAC accreditation has been granted by one of the primary accrediting authorities, it can be used to obtain secondary accreditation in other states that participate in NELAC.

When is Certification Needed?

So when do you need certification and what certification do you need? When performing testing to meet any local, state or federal requirement you should be using a laboratory that maintains certification for the analytes being requested. In most cases, the laboratory should be certified in the state from which the work is being done. In some instances, some states will recognize NELAP accreditation in lieu of state certification, but you should get this approved through the regulator requiring the testing. Another instance in which you should seek a certified laboratory is when performing testing that will be used in litigation; this is to ensure the laboratory analyzing the samples is following the appropriate procedures, thereby minimizing the possibility of errors.

If the results are not needed to meet regulatory requirements, or to be used in a court of law, you are free to use the laboratory of your choice; however it is advisable to use a laboratory that maintains some sort of certification to ensure quality data.

Sample Collection

There is a common misconception that you can collect water in any container and drop it off at the laboratory. When collecting samples to meet regulatory requirements, there are strict guidelines for collecting samples based upon what you need to have the sample tested for. EPA and Standard Methods have detailed instructions on how to test the sample, and spell out in great detail the amount of sample required, type of bottle, preservative required, and the holding time for running the analysis. The amount of sample required can also be dictated by the regulations you are trying to meet; for example, when collecting a lead sample, one must collect a 1-liter sample, even though the analysis can be done with a few milliliters. The type of bottle used is also crucial for accurate analysis.

The following are some examples of how the bottle type used will affect the analysis:

  • Microbiological samples should be collected in a properly sterilized bottle, for obvious reasons;
  • Certain analysis require collecting samples in plastic bottles while others require glass sample containers. For example, you would not want to collect a silica sample in a glass bottle, and a sample being collected for odor should be in a glass bottle as certain plastics can affect detection of odor;
  • There are some chemicals that break down when exposed to light, so sample collection requires an amber colored bottle to prevent the chemical from breaking down if it is present in the sample; and
  • Volatile organic chemicals should be collected in special vials with an air- tight cap with no air bubbles. This is because volatile organics want to evap- orate into the air and if there is air present in the sample it can contain some or all of the volatiles that may have been in the sample.

Depending on the type of analysis, a preservative may be required to ensure the analyte being tested doesn’t break down into something that could not be detected. Lastly, there are specified holding times, and this refers to the amount of time a laboratory has to run a sample after it has been collected. Certain analytes have short holding times, such as bacteria, pH and chlorine, while most metals can be analyzed up to six months later.


When deciding where to send samples for testing, having a basic knowledge of the regulations concerning laboratory certification and any regulations that apply to the analytes you want to test, will help you pick a laboratory that will fit your needs. A reputable laboratory should be able to help you determine what type of laboratory certification is required, if any, for the specific sample testing you are looking to have performed. Laboratories will typically provide all the sampling containers and collection instructions to ensure the accuracy of the sampling. There are some cases in which samples have already been collected and cannot be re-sampled, so discuss this with your laboratory representative and they can discuss the potential impact on the results. wqp

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