There are a variety of ways that drugs get into the environment; one of the most significant is when unused medications are poured down the drain or flushed down the toilet. Convenient, secure drug disposal programs work to keep medications from getting into our water supplies. The Diamond Bar-Walnut Sheriff's Station provides a safe and convenient monthly collection of unused or expired prescription drugs for safe disposal. Collections are held the second Tuesday of every month from 10 a.m.-1 p.m. The next collection takes place Tuesday, June 12.