It seemed like a good idea at the time.

The folks at Lowes insisted that repairing an irrigation system back-flow prevention valve was easy. “Anyone can do it,” I recall someone in the plumbing section assuring me. I bought  the necessary equipment— polyurethane pipe including elbow joints, connectors, a pipe cutter, tape, glue (which consisted of two parts, one purple and one clear)—and left with near complete confidence that I would have my irrigation system functional in short order.

I followed the instructions to the letter. I measured and cut with precision, attached the pieces together, applied the glue, first the clear and then the purple, or was it first the purple and then the clear?  It all fit snugly.

Instructions said to wait an hour before turning the water on. Taking an overly cautious approach, I gave it 90 minutes before I opened the valves and turned on the water. Nothing happened—for about 15 seconds. Then the whole system blew up in my face, spraying water all over the porch and soaking me to the bone. I turned the valves off to stop the eruption, sat down on the steps—and laughed. It was too funny not to.

That little plumbing project ending up costing me a few hundred dollars after the plumber replaced several items destroyed by my inept repairs. The unintended consequence of my do-it-yourself endeavor resulted in me taking a soaking— physically and financially.

The law of unintended consequences is as certain as sunrise. I should have called a professional to begin with.

It happens on a larger stage, too. Recent tariffs imposed by the Trump Administration may prove the point.  Monday, President Trump approved tariffs on washing machines and solar panels manufactured in China with the good intention of protecting U.S. manufacturing. The tariffs include a 30 percent duty on imported solar panel technology and 20 percent for the first 1.2 million washers imported in 2018; tariff goes up to 50 percent after that threshold is met.

At least one appliance company announced a price hike to cover the increased cost of washing machines. Consumers will pay more.

U.S. agriculture stands to lose, too. China is a crucial market for U.S. soybeans, grains and other commodities. Tariffs on solar panels could jeopardize agriculture trade if China retaliates, which is a near certainty. And China has other market options; Brazil comes to mind.

Good intentions, perhaps, but unintended consequences may harm U.S. farmers and consumers.  Lessons: Leave plumbing to plumbers. A campaign promise makes a good sound bite, may be based on good intentions, and may stir up the base, but the consequences can blow up in your face.

Who benefits? In my case, it was the plumber.  For U.S. trade, it’s hard to find a winner.