An Electric Hum

It's about 2:30 in the morning, and I am sound asleep. In my dream I am standing on a stage somewhere, about to receive the Glockenspiel award for excellence in humour writing. But there is a hum coming from somewhere. An electric hum. The kind of hum that gets under your skin and irritates your never endings until the hairs on your arm stands up.
In spite of my best efforts to see the dream through to the part where I actually get my award, I awake to discover that I am in bed, tossing restlessly.
But the hum has not faded with the dream, and suddenly I am wide-awake. Few things alarm me like my house making unusual noises. Nothing, for instance, can freeze my blood like the unaccounted-for sound of running water somewhere in my home. "Who left the water on?" I'll shout, chasing around the place until I find the garden hose that has been left running - usually by me, or the toilet that has been flushed. Unaccounted-for running water in a house is bad. It means burst pipes, invariably in the most inaccessible part of the house, and huge repair bills. Trades people with large trucks and very noisy tools appear shortly after the unexplained sound of running water, and they make noise and dust for several weeks, after which they present you with a repair bill that would pay the debt of most developing countries.
Hums are also very bad. Hums are associated with electric motors in dishwashers, motors that have seized up and will shortly result in the dishwasher springing a leak all over the hardwood floor in the kitchen, or with laundry machines that will also seize and leak through the floor into the finished basement, or with dryers that catch fire or with furnaces that fail on the one night of the winter when the temperature plunges to 30 below. Hums are very bad indeed.
I lie in bed in the dark and listen. The hum seems to be emanating from the headboard, but that's silly, there are no electric motors in the headboard, I'm pretty certain of that. I check the lamp, it's not humming, neither is the alarm clock.
I hop out of bed and put my ear to the bedroom wall. Yep, the house has definitely developed a serious hum.
"Whaddareyadoin?" My wife mumbles.
"We've developed a hum," I explain, my head pressed to the doorjamb.
"Checkit innamorning," she suggests helpfully, and drops directly back into REM sleep.
But there is no rest for me. You ignore a nocturnal hum at your peril.
Slowly and meticulously I track the faint, elusive hum, through the house, room to room, floor to floor, attic to garage, appliance to appliance, until I finally track it down and corner it in the basement. There it is, under a stack of boxes and ancient suitcases, beneath a large, black plastic lid: the sump pump. The electric motor of the pump, submersed under two feet of dark, murky water, has seized, and is humming away ineffectually, unable to pump.
The mystery has been solved. I unplug the sump and head back to bed, secure in the knowledge that all the creaks, bumps, pops, hums, gurgles and clicks of the house are familiar and harmless.
"Zzzzzzz," says my wife as I slip under the covers.
When the plumber shows up the next day, I tell him about the problem: how it woke me, and how I finally solved it. My wife shakes her head in disbelief. "How could you possibly be awakened by a hum so faint? You, who slept through the howling of the children when they were babies."
The plumber and I look at each other. The answer is easy, the babies might have cried when they leaked in the night, but their leaks were never large enough to do any serious damage. Had they hummed, it would have been a different story.