What Are the Process and Best Practices to Collect Water Samples?

In order to get the most accurate results, samples need to be collected correctly. While each lab's sampling standard operating procedures (SOP) may differ, there are some general best practices for collecting samples.

Before getting into sample collection and field practices, determine if samples need to meet regulatory requirements. If the samples are to meet regulatory requirements, the procedure may be dictated by the regulation.

Let's discuss some basics when collecting samples. Sample collection bottles, materials, and Water Sampling Equipment.

In the equipment list commonly used devices include electric submersible pumps, bailers, suction-lift pumps, positive displacement bladder pumps, and Groundwater Sampling Pump.

Sample collection bottles and materials

Because certain bottle sizes and preservatives used vary slightly, it's better to have sampling bottles from the lab performing the examination.

Nothing is more annoying than being caught off guard in the field, so plan ahead as much as possible. Because certain bottle sizes and preservatives used vary slightly, it's better to have sampling bottles and the Well water sampler from the lab performing the examination.

The sort of bottles used will be determined by the methods that will be used. Metal samples, for example, are typically collected in plastic bottles, whereas volatile organics and pesticide analyses are typically collected in glass containers.

Bottles that are used to collect bacteria samples should be sterilized. The container's size is critical for ensuring that you have enough samples for the analysis. Regulation may also have an impact on container size, since bigger samples may be required to achieve lower detection limits.

Holding times and preservatives

Chemical preservation may be feasible, depending on the results of the analysis. Sodium thiosulfate, a dechlorinating agent, is a typical preservative used to prevent chlorine reactions. For bacteria analysis and volatile organics, sodium thiosulfate is utilized.

Wherever possible, many laboratories will give pre-preserved bottles, although some analyses require field preservation. Hydrochloric acid, which is utilized to inhibit any microbial activity that could reduce the pollutants while in transit to the lab, should be used to further protect volatile organics in the field.

Temperature preservation is the most common type of conservation; most analyses require that samples be kept cool, arriving at the lab between four and six degrees Celsius. Contaminants are less likely to break down in transit due to the colder temperatures.

Sampling techniques

You'll need a representative sample when collecting samples, and you should run the water for several minutes when sampling well water to ensure that you're obtaining water directly from the well and not from a source that's been sitting in a storage tank or pipes.

Remove any aerator from the spigot before turning on the water. Using local metrics like pH, temperature, and conductivity might help you figure out if you've run the water long enough. Take measurements every two to three minutes, and collect samples once you have three consistent measurements in a row.

Sampling toolkit

Make a sampling kit if you sample on a regular basis. A decent sample kit would include all of the supplies and equipment needed to conduct an onsite analysis, such as pH, temperature, and conductivity meters, as well as standard solutions for correctly calibrating equipment.

In some cases, having tools on hand, such as a wrench for removing tough aerators, screwdrivers, and a flashlight might be useful. Supplies like gloves and alcohol swabs can be kept in the same place as the rest of your sampling equipment.

Sampling points

The location of the samples will be determined by the analysis' goal. If you're taking a sample to establish a baseline of water quality for a private well, for example, you should do it before using any treatment devices.

Because many homes will not recognize a sediment filter as water treatment, it is crucial to look for treatment equipment. Unless there is a specific water quality issue at a different tap, such as a bathroom sink, obtaining a sample from the kitchen sink is usually advised.

To assess if treatment equipment is running properly, you may need to gather "before" and "after" examples. Where you got the sample is usually specified to meet a certain regulation.