Vespasian imposed a Urine Tax (Latin: vectigal urinae) on the distribution of urine from public urinals in Rome's Cloaca Maxima (great sewer) system. (The Roman lower classes urinated into pots which were emptied into cesspools.) The urine collected from public urinals was sold as an ingredient for several chemical processes. It was used in tanning, and also by launderers as a source of ammonia to clean and whiten woollen togas. The buyers of the urine paid the tax.
The Roman historian Suetonius reports that when Vespasian's son Titus complained about the disgusting nature of the tax, his father held up a gold coin and asked whether he felt offended by its smell (sciscitans num odore offenderetur). When Titus said "No," he replied, "Yet it comes from urine" („Atqui ex lotio est“).
The phrase Pecunia non olet is still used today to say that the value of money is not tainted by its origins. Vespasian's name still attaches to public urinals in France (vespasiennes), Italy (vespasiani), and Romania (vespasiene).