Sterile PCR water Ultrapure water (Type I), sterile, nuclease-free, free of DNA and RNA PCR water is ultrapure water that has been proven to be free of nucleases, DNA and RNA. Ultrapure water is specially purified water whose purity exceeds that of demineralised and distilled water. The difference to the quality of distilled or demineralised water can be seen in the electrical conductivity of ultrapure water of ≤0,075 μS/cm. Since the water molecule is an ampholyte that can react with itself, even ultrapure water has a low electrical conductivity. PCR water is suitable for use in sensitive molecular biology applications such as PCR, RT-PCR, cDNA synthesis or sequencing. Each batch is tested by PCR to exclude contamination by DNA and nucleases.