The Pre/Postnatal City Water Basic is an affordable testing option which looks at the most common contaminants in city supplied drinking water. While city supplied water is generally safe, there are contaminants like lead and disinfection by-products that can be formed after water leaves the treatment plant. These contaminants have been associated with birth defects, miscarriages and learning disabilities in children. This test includes a few basic heavy metals, chlorine, chloramine and trihalomethanes.