What is the best water for soap making?

There are numerous types of water for soap making.  There is well water, municipal tap water, distilled water, reverse osmosis water, de-ionized water, alkaline water, soda water, milk water, coconut water and rainwater to name a few.  With all these choices it may seem that finding the best water may be a bit daunting!  But in reality it's quite simple.  We are looking for the purest water of them all.  Distilled water stands out by name alone as the purest water to use.

Distilled water is the most pure because it has been super heated into steam vapor which is then returned back into a liquid form where it is transformed into what we know as distilled water.  This process leaves behind the minerals such as calcium, magnesium, sodium, iron and zinc because they will not vaporize.  Steam distillation of water also removes the electrical charge of water to almost zero.  This is because the dissolved solid minerals that conduct electricity have been reduced to nearly zero.  The TDS (Total Dissolved Solids) of distilled water is a very low number of 0 to 5 PPM's (Parts Per Million).

Why is this a good thing for soap making?  Reducing the impurities found in the water will reduce the impurities that may cause a reaction of spotting or discoloration in your soaps. 

Should I avoid using tap water for soap making?

The simple answer is yes!  Avoid using municipal city tap water for soap making because it typically contains chlorine and fluoride.  There are reports in some cities across the United States that forever chemicals have been found in their municipal water supplies.

Where I live, the tap water is chlorinated moderate to heavy.  When I go to wash my face in the morning the smell of chlorine is strong.  When I'm running hot water the steam gives off a chlorine odor as well.  The chlorine is said to reduce the lathering ability of your soaps.  For this reason I will use distilled water for soap making.

Another compound found in tap water is fluoride.  This compound is known to be unfavorable for good health in the long run.  If you choose to use tap water for your soap making, the results from fluoride in the water may be inconclusive or non existent. Either way, I will side with health and use distilled water for soap making. 

Forever chemicals are now being found in municipal water supplies around the country.  According to the gao.gov website article dated: 10/22/24, "Synthetic chemicals called per - and polyfluoroalkyl substances - PFAS - have been around since the 1940's."  "Frequently referred to as 'forever chemicals' because they break down slowly, PFAS can linger in the environment for a very long time."  They are used in products like nonstick cookware, waterproof clothing, firefighting foams, some carpeting, furniture, takeout containers, some dental flosses and makeup."  Activated charcoal can be used to adsorb these forever chemicals.  I avoid the uncertainty of tap water is by using distilled water in my soap making. 

What about using well water for soap making?

Unless you've tested your water on a regular basis or you have installed a water purification system, there is no way of knowing the mineral content of your water.  There is no way of knowing what the TDS levels are in your well water.  With that being said, avoid using well water for making your soap.  The known or unknown results from the impurities in well water is best avoided by using distilled water.

What is reverse osmosis?  Can I use this water for soap making?

RO or reverse osmosis is another method by which to purify water.  But to explain reverse osmosis we need to know how osmosis works first.  I'm sure you remember osmosis from elementary school science, but did we ever understand how osmosis worked?  Well, according to Websters college dictionary osmosis is: "The tendency of a solvent to pass through a semipermeable membrane, as the wall of a living cell into a solution of higher concentration, so as to equalize concentrations on both sides of the membrane." 

Here is a video from RegisteredNurseRN that explains osmosis in simple terms, "Higher concentrations of water (with few solutes) will move to a lower concentration of water (with higher solutes)".  A good example would be how tree roots gather water by osmosis.  It occurs naturally without any effort. 

Now, in reverse osmosis you have a lower water concentration with a higher amount of dissolved solids.  This is the water you want to purify.  With reverse osmosis, pressure is used to push the lower water concentration (with higher dissolved solids) through the semipermeable filter in reverse of what nature does thereby purifying the water to a higher concentration of water with very low solutes.  The result is water purity of 0 to 5 ppm's (parts per million) of TDS (total dissolved solids). 

Using RO or reverse osmosis water for soap making is just as good as using distilled water.  The only difference is the purification method.  Both methods will achieve excellent water purification results.