Henry went out to the front of the apartment building and turned off the main water valve. No one was home in the building except Stanley, so Henry didn't have to warn the neighbors about the shutoff. Back in the bathroom, Henry flushed the toilet. Then he used a couple of rags to dry and clean the bottom of the toilet tank. He unscrewed the plastic Fluidmaster 400A Fill Valve and removed it. He replaced it with a new fill valve. "When the water keeps running, it's usually your fill valve. It could also be the flapper, but your flapper looks okay. Plus, it's a weird-looking flapper. I'd probably have to special order it."

Henry tightened the plastic nut below the tank, securing the fill valve. "You mustn't over-tighten this, because it'll break," he said. "In the old days, we used rubber gaskets and metal nuts and washers. Nowadays, everything is cheap plastic." He went back outside, turned on the main valve, and returned. He flushed the toilet, waited for the bowl to refill and for the new fill valve to shut off the water. It shut off exactly at the Water Line mark.

"We got lucky," Henry said. "I don't have to fiddle around adjusting the fill valve. That's good, because I'm a little late for another job right now." Henry flushed the toilet again, and watched the bowl and the tank fill. "That does it," he told Stanley. Stanley thanked him and paid him.

Three hours later, Stanley noticed a puddle of water, hardly bigger than a quarter, on the bathroom floor. He called Henry, who said the plastic nut just needed a little tightening. But because he was working all that day on another job, he wouldn't be able to come over until tomorrow. He told Stanley to put a big plastic bowl under the tank and not to worry. "It's just a tiny leak. Your bathroom won't get flooded."