It is not okay. Tap water contains variable mineral content, especially calcium and magnesium, which can affect the performance of the SAP content in the diaper core. It’s advisable to use 100% distilled water to avoid these fluctuations unless you’re certain of consistent water hardness. pH variations in tap water can also impact diaper performance. To minimize variations related to iodine salt, we recommend using 99.9% chemically pure NaCl, available in most chemical stores. If you opt for the same brand of iodized table salt, the expected variation is minimal, but it depends on your testing precision needs.