Yes, DNA is present in tap water.
Based on the provided study, various types of water sources, including water disinfected at the point of use and chlorine-treated water (which includes tap water), all showed the presence of DNA. This indicates that even after disinfection processes, DNA can still be detected. Notably, the study found DNA from FIB (faecal indicator bacteria) in these water samples. Despite the presence of DNA, including FIB DNA, the treated water in the study was considered suitable for drinking.
Key Findings:
| Water Type | DNA Present? | Cultivable Bacteria Present? | Suitable for Drinking? |
|---|---|---|---|
| Bottled Drinking Water | Yes | No | Yes |
| Disinfected Water at Point of Use | Yes | No | Yes |
| Chlorine Treated Water | Yes | No | Yes |
- The study confirms that disinfection processes, while effective in removing live, cultivable bacteria, don't eliminate all traces of DNA.
- Presence of DNA from bacteria (like FIB) doesn't necessarily mean that live, infectious bacteria are present. The DNA could be from dead or non-viable organisms.
- The study highlights that water can be considered safe for drinking even if DNA is detected.
Understanding DNA in Water
The presence of DNA in water, especially from bacteria, is common. DNA is a resilient molecule and can persist even after the microorganism it came from is no longer viable. Disinfection methods target living organisms, not their DNA. Therefore, the detection of DNA in water, including tap water, does not automatically mean that it is unsafe for consumption. The main concern is the presence of live, disease-causing organisms, not their DNA.
