Feb. 4—If you are a cashier, you'd better not overcharge Murrysville resident Mary Bach. She will find out, she will take your store to court — and she likely will win.

Bach, 78, recently won a $100 district court judgment against Walgreens in Murrysville after she discovered the store was imposing a tax on toilet tissue, which is not permitted under state law. Bach has won judgments in eight civil cases dating to 2008, according to court records.

Bach's civil suits cite the Unfair Trade Practices Act and Consumer Protection Law, which went into effect in 1968. Citizens can sue for the amount of their damages or $100, whichever is greater.

Bach spoke with the Tribune-Review about holding stores accountable. This interview has been edited for length.

Q: How did you discover that you were being taxed for toilet tissue?

A: In mid-November, I bought their brand toilet tissue for my household, priced at two for $10 or one for $6. I purchased two to get the deal, along with a variety of taxable and other nontaxable items. I didn't pay close attention to the tax because it seemed within reason for what I purchased.

The next time I purchased the same toilet tissue, I carefully calculated the tax based on what I had purchased, and I had been charged tax on the toilet tissue. I went back to the previous receipt and added everything up and saw I had also been charged tax the first time. The next shopping trip, I bought only the toilet tissue, and the tax was a very obvious line item. I mentioned it to the cashier, who was disinterested.

I subsequently bought the same toilet tissue in Penn Hills, Wilkinsburg, Greens­burg and York and was charged tax in every location, so it has been endemic in their system.

Q: So this wasn't a case of a cashier accidentally adding tax to your purchase?

A: It was ringing up automatically in their system ... 7% in Allegheny County and 6% elsewhere. The cashier had no control. Of course, when I mentioned it to them, they could have called a supervisor or told someone in charge to look into it. I am of the opinion that no one did anything to follow up or inquire in any way.

Q: Toilet tissue is not taxable because it is considered a "necessity," correct?

A: The old necessity-versus-luxury argument is null and void. Pet food is certainly necessary for an animal to live, yet pet food is taxable. Toothpaste and toothbrushes are not taxable, but deodorant and shampoo are. Dog and cat medicated shampoos are not taxable, so we pay tax to wash our own hair, but not Rover's. Facial tissue is taxable, as are paper napkins and paper towels, but not toilet tissue. A rotisserie or fried chicken from the grocery deli is taxable, but a beautifully decorated cake from the grocery bakery is not taxed. Bottled water is not taxed, unless it is flavored bottled water. Carbonated beverages are taxed, but tea products are never taxable.

Thread, zippers, cloth, yarn, buttons and other notions are not taxed if they are for clothing for people, but those same identical items are taxable if used for pillows, doll clothes, slipcovers, craft items, or anything that isn't clothing for people.

There is a comprehensive sales tax guide on the Department of Revenue website.

Q: Do you have any other lawsuits pending?

A: I have now sued the Penn Hills Walgreens because, on Jan. 20, they were still charging tax on toilet tissue. I have a small-claims action for $100 in March before Judge Anthony DeLuca.

Patrick Varine is a Tribune-Review staff writer. You can contact Patrick by email at pvarine@triblive.com or via Twitter .