The best way to avoid contamination is to use our sampling kits and follow the instructions provided. NatureMetrics filters are fairly robust to contamination because the filter membrane is enclosed within a plastic housing. However, you need to take care not to introduce contamination via the vessel you use to collect the water from the waterbody or to hold it while you filter. For this reason, the NatureMetrics sampling kits contain a sterile single-use collecting bag as well as gloves to prevent the introduction of your own DNA into the sample. If you are using a bucket to collect and/or hold the water, this will need to be cleaned with a 10% solution of household bleach to remove any traces of DNA, the bleach should be disposed of responsibly and then rinsed thoroughly with clean, distilled water before sampling.