Flushing your pills, or just keeping them on hand, could be sharing them with your neighbors.
Traceable levels of birth control, antidepressants, opioids and illegal substances -- like cocaine -- are being found in drinking water across the United States.
For now, "they are harmless" to humans, according to Dr. Frank Lovecchio with the Banner Poison Drug & Information Center, but highlight a much bigger problem.
"The number one reason you die from the age 25 to 45 is a drug overdose," he said. Unfortunately, deadly overdoses involving prescription drugs are a "daily occurrence" in the Valley.
Lovecchio said one-third of people who overdose on prescription medication acquired them from a friend, family member or neighbor. Instead, drugs should be disposed of responsibly.
How do you properly dispose of prescription pills? Find a designated drop site near you.
The DEA has a searchable database of locations.
Three Banner pharmacies in the Valley also recently installed secure Medsafe containers:
1. Banner Estrella Medical Center: 9201 W. Thomas Rd., Phoenix, AZ 85037
2. Banner Gateway Medical Center: 1900 N. Higley Rd., Gilbert, AZ 85234
3. Banner MD Anderson Cancer Center: 2646 E Banner Gateway Dr., Gilbert, AZ 85234