It doesn't matter whether you grab it at Costco or Walmart or whether it's Cottonelle or Charmin. Toilet paper is always stark white, which makes every bit of residue from its selfless mission to clean one’s rear end visible. But assessing whether a proper wipe job has been done is not why toilet paper is white.
According to Reader’s Digest, toilet paper is made from cellulose fiber harvested from trees or recycled paper and then mixed with water to create wood pulp. Manufacturers then bleach the pulp to remove the polymer lignin, a process that creates softer tissue. (Removing lignin also extends the life of the paper. With it, your tissue might age as poorly as newspaper.) Naturally, that same bleach also renders the pulp white. Otherwise, there would be brown streaks—and not the kind you’re thinking of. The glue holding the cellulose together is usually darker in color.
Obviously, white toilet paper makes it easier to determine when a person has finished cleaning up after themselves. But it’s not unheard of to find colored toilet tissue. In the 1950s, pastels were popular, with people looking to match the color of the paper with their bathroom design. Consumers picked up lavender and beige rolls until the 1980s, at which point concerns over skin irritation and possible environmental damage due to the dyes saw them disappear from the market. Other countries, like South America and Europe, offer toilet paper in different colors. In France, even scented toilet paper can be found on shelves, which seems like it would be a losing battle considering what the fragrance is up against.
As festive as that all sounds, Americans seem to be pleased with white bathroom tissue. Considering dyes only add to the cost, it would be like flushing money down the toilet.
[h/t Reader’s Digest]