My water stopped after filling the pool. Did my well run dry?

What drawdown actually is

Your well is not a tank of water. It is a hole in rock, and the water in it stands at whatever level the surrounding rock holds it at. That is the static level, and on a well in these hills it sits 20 to 60 feet below the ground on a normal day. The pump hangs far below that, near the bottom of the hole, and the column of water standing above the pump is the only water you have on hand at any given moment.

Put a number on it. A standard 6 inch casing holds about a gallon and a half per foot of water column, so a 400 foot well with static at 40 feet and the pump set at 380 is carrying roughly 500 gallons. That sounds like a lot until you look at what you were filling. An 18 foot round above ground pool is around 7,500 gallons. A modest 16 by 32 in-ground pool is 17,000 to 20,000. You empty the standing column in the first hour, and after that you live on whatever the rock hands over.

Once the standing column is gone, the water level in the hole starts falling toward the pump. The level while pumping is the pumping level, and the distance it drops from static is drawdown. Every well draws down. A strong one drops ten feet and holds there all day. A weak one keeps falling until the level reaches the pump intake, and that is the exact moment the kitchen faucet starts sputtering and then quits. Nothing broke. You just took water out faster than the well makes it, for long enough.

Why a low yield rock well recovers so slowly

There is no aquifer under the Highlands in the way people picture one. There is no bed of sand and gravel holding water like a sponge. There is Precambrian gneiss and granite, solid rock, with water living in the cracks that run through it. Your well produces exactly as much as the fractures it happened to intersect are willing to give, and drilling deeper does not create a fracture that is not there. That is why two houses on the same road can have a 15 gallon a minute well and a 2 gallon a minute well.

Yields of 1 to 5 gallons per minute are normal here, and plenty of families run for decades on 2 or 3 without knowing it. A 3 gpm well makes 180 gallons an hour and better than 4,000 a day, far more than a household uses. The daily total is not what gets you. The rate is. Fill a 17,000 gallon pool from a 3 gpm well and you are asking for roughly 95 hours of continuous pumping.

Recovery runs the same arithmetic backwards. Fractures push water back into the borehole at feet per hour, not feet per minute. That is why the fix is time, and why flipping the breaker on after twenty minutes just runs the pump dry a second time on the little that trickled in. Overnight, a 2 gpm well puts roughly a thousand gallons back in the hole. Twenty minutes gets you forty.

What running dry does to the pump

A submersible pump is a motor with a stack of impellers on top, hanging on a pipe hundreds of feet down, and the motor is cooled by well water flowing past its shell on the way up. Stop the flow and nothing carries the heat away. A half or three quarter horsepower motor spinning in air can break down its winding insulation in well under an hour, and some fail in minutes. It does not warn you. It reads fine one day and open circuit the next.

The wet end takes damage too. The thrust bearing carrying the whole weight of the water column is water lubricated, and so are the shaft bearings and seal faces. Dry, they gall. Then the water comes back loaded with silt, because the level dropped into the part of the hole where sediment sits, and that sand runs through the impeller stages and machines them out. A pump run dry twice often keeps working and quietly loses a third of its output.

Then there is the electrical side. With no water at the pump, pressure never builds, so the pressure switch never opens and the pump runs until something stops it. On many setups the thermal overload trips, cools, restarts, and repeats all night. Each restart is a locked rotor surge the motor, the capacitor and the contacts all pay for. That is why the first instruction here is the breaker rather than give it another try in a bit.

Bringing it back without wrecking the house plumbing

Kill the power at the panel, not at a disconnect or a pressure switch lever, and leave it off. Take the load off so nothing drains what comes back in. Then walk away for as long as you can stand it. Four hours is the floor, overnight is the right answer, and if you have been hammering the well for two days, give it a full day.

Before you go to bed, shut the water heater off. If the house ran completely out, air got into the top of that tank, and electric elements that fire with their tops exposed burn out in a matter of seconds. It costs nothing to turn it off and it prevents the single most common piece of collateral damage from a dry well. Leave it off until the cold side of the house is running clean and steady.

When you restore power, open one outside hose bibb and nothing else, and let it run a full ten minutes before any fixture inside the house is touched. The first water up will be cloudy, gritty and rust colored, because the pump stirred up everything that had settled in the bottom of the hole. You want that landing on the driveway. Send it into the house and it packs sediment into the water heater, plugs the cartridge filter, loads every aerator screen, fouls a softener bed and puts grit in the toilet fill valves. Ten minutes at the hose is the difference between a scare and a weekend of plumbing repairs.

Once the hose runs clear, work the house cold side first, one fixture at a time, letting each spit and clear before moving on. Rinse any aerator screen that slowed down and change the sediment cartridge, because it caught the worst of what got past you. Turn the water heater back on last, once a hot tap runs a solid stream with no air in it.

Ran dry, or the pump is dead?

The whole diagnosis is in the timeline. Water that quit at the tail end of a big draw and comes back after a rest ran the well down. Water that quit and does not come back after a full night with the breaker off is not a drawdown problem. That is a pump, a wire, a control or a split drop pipe, and no amount of patience fixes any of those.

Watch the pressure gauge when you restore power. A recovered well climbs steadily to the cutoff setting and holds. A well that is still low climbs partway, stalls, then falls back while the pump keeps grinding, and a hand on the pipe at the tank feels it surging. A dead pump does not move the needle at all. A breaker that trips the instant you reset it is an electrical fault, not a dry well, and that needs somebody with a meter.

When we come out, we drop a water level meter down the casing for a real static number, then run the pump and watch the level fall to get a drawdown rate and a recovery rate. Twenty minutes of that says whether you have a 2 gpm well that got overrun or a 10 gpm well with a failing pump, and those two get very different bills. We read amp draw at the same time, because a motor moving water and a motor spinning in air read differently on a clamp meter.

How to not do this again next summer

First, find out what your well actually makes. Put a five gallon bucket under an outside spigot, open it wide with nothing else running, and time it. Sixty seconds is about 5 gpm. Two and a half minutes is about 2. The pressure tank contributes to the first part of the fill so the number is rough, but it is honest enough to plan around, and most homeowners have never measured it.

Then do the arithmetic before the hose goes in the pool. Divide pool gallons by your gallons per minute, divide by 60, and you have hours. If the answer is more than about eight, fill in stages: four to six hours a day for several days, shut down overnight, let the well catch up. If it is north of forty hours, have it trucked. A bulk water delivery runs a few hundred dollars and is cheaper than a pump and a service call.

The same logic covers the rest. Do not run the pressure washer while somebody is doing laundry. Do not fill the pool the same weekend as the hot tub. Water the garden at six in the morning instead of during the shower hour. On a 2 gpm well the whole trick is spreading the draw across the week instead of stacking it into one Saturday afternoon.

If you plan to keep asking a lot of a small well, there is hardware for it. A pump protection control that senses a dry run and locks the pump out is the cheapest insurance in this trade, a few hundred dollars installed. Lowering the pump another twenty or thirty feet, where the hole allows, buys real storage. On a genuinely low yield well the answer is often a basement storage tank the well fills slowly all day, with a booster pump feeding the house, so the house sees strong pressure and the well never sees a hard draw. Where the well itself is the limit, hydrofracturing can open existing fractures and add yield. Call 973-853-1550 and we will tell you which one you need after we measure it.