That bong with the leftover water in it? It can get you in big trouble.

The Minnesota Supreme Court ruled 4-3 on Thursday that bong water with traces of methamphetamine was a “mixture” with a controlled substance — and not just “drug paraphernalia” — sending the case of a Rice County mother back to district court for retrial.

Sara Ruth Peck, now 46, of Faribault, was charged with first-degree drug possession in September 2007 after the South Central Drug Investigation Unit searched her home and found a glass bong, a red butane torch and a glass pipe. Peck was at home with her children, ages 12 and 8.

The St. Paul crime laboratory analyzed a sample of the water from the bong; it tested positive for meth, the complaint said.

Peck also was charged with felony fifth-degree drug possession and child endangerment, a gross misdemeanor.

The district court in Rice County threw out the first-degree drug possession charge after she argued that the pink, fruity bong water did not constitute a “mixture” under state law. Peck intended the bong water to be part of the bong, or drug paraphernalia, the court concluded.

The state Court of Appeals agreed.

The law says that a person is guilty of first-degree possession if he or she possesses one or more mixtures of 25 grams or more of meth. In Peck’s case, the bong water weighed 37 grams.

In his majority opinion, Supreme Court Justice G. Barry Anderson wrote that state law was clear and that the courts “must give the statute’s words and phrases their plain and ordinary meaning.”

The law defines a mixture as “a preparation, compound, mixture, or substance containing a controlled substance, regardless of purity.”

A dissenting opinion said the majority ruling “misapplies the plain-meaning rule … runs counter to the legislative structure of our drug laws, does not make common sense, and borders on the absurd,” wrote Justice Paul H. Anderson, who was joined in dissent by justices Alan C. Page and Helen M. Meyer.

He said the 37 grams of bong water constituted about “2 1/2 tablespoons.” A first-degree drug conviction calls for a presumptive sentence of more than seven years in prison.

“Rice County’s decision to charge Peck in a manner far more serious than what was intended by the legislature represents the kind of counterproductive activity that leads unnecessarily to increasing incarceration rates and wasted taxpayer money,” Paul Anderson wrote.

If the bong water is treated as paraphernalia, he continued, the defendant would receive a fine of no more than $300 and a petty misdemeanor conviction.

Rice County Attorney Paul Beaumaster applauded the majority opinion Thursday.

“It’s not just about whether bong water can hold a controlled substance,” he said. “The question before the court is whether or not the Legislature had already set out what controlled substances are.”

It is the Legislature’s job — not the courts’ — to decide “what qualifies and does not qualify to be a crime,” Beaumaster said.

His office will pursue prosecution, he said.

Emily Gurnon can be reached at 651-228-5522.