The submersible is installed by lowering it down the well on the end of a string of pipe. The pipe is added one length at a time as the submersible is lowered. One-inch diameter pipe is used most often on residential installations, but larger pipe is occasionally required if higher rates of water production are needed.

For smaller submersibles installed to depths of about 500 feet, schedule 80 PVC (plastic) pipe with threaded couplings can be used. This pipe has a thicker wall than similar pipe that you might be used to seeing in irrigation systems for example. The schedule 80 pipe is designed for the task. It’s lighter and less costly than steel, and doesn’t corrode. A safety rope is installed alongside the PVC pipe in order to have a means of removing the submersible in the remote event that the pipe should break. A torque arrestor, which is a device to center the pump and minimize its twisting on startup, is installed above the pump.

In some cases, galvanized steel pipe is used. That’s because beyond a certain depth, the combined weight of the submersible, pipe, wire, and water contained in the pipe, would be too heavy for PVC pipe. Steel pipe is also used at shallower depths for larger submersibles, where the twisting of the motor when it starts (torque) might damage PVC pipe. Galvanized steel pipe is stronger, but is also heavier, and subject to eventual corrosion. A safety rope is not required in these installations.

No matter which type of pipe is used, one-way check-valves are installed at intermediate distances along the pipe string, to prevent water from draining back down the well when the submersible is shut off. The wire, and safety rope if installed, are lowered at the same time as the pipe string, and securely fastened to the pipe along its length.

The pipe string exits the well casing through a well cap. Surface plumbing varies with each installation, but may include a hose bib (for taking water samples), and a pressure-relief valve to vent excess pressure in case of malfunction.

Pressure tanks of various sizes are used to supply water pressure even when the submersible is stopped. A pressure tank is cylinder shaped, made of steel or fiberglass, and is generally about four feet tall and two feet in diameter. Inside is a rubber bladder, which takes up about half of the capacity of the tank. The remainder of the tank (the top portion) is air space. When the submersible is running, water is pumped into the bladder. As the bladder fills, it enlarges, causing the air in the space above to become compressed (the water itself cannot be compressed). Once the bladder is full, a pressure switch shuts off the submersible. When a faucet is opened, water flows out of the bladder, pushed by the compressed air. After a certain quantity of water is used, the bladder is near empty, and the pressure switch activates the submersible again to cause the cycle to start over.

On new installations, the pressure tank may be omitted temporarily during the construction phase. The pump can still be operated manually using a generator for instance, providing water for the building construction process. The tank, associated plumbing, and controls can be added later when needed.

Systems consisting of a submersible and a pressure tank are commonly called “single-pump systems” (figure 1). Systems using a submersible, a storage tank, a pressure pump, and a pressure tank are called “two-pump systems” (figure 2). Other equipment is also sometimes used, such as solar powered pumps, or constant pressure delivery systems. But the two drawings below represent the most common equipment combinations. Click on either drawing to view a larger version.

      

Storage tanks come in many types and sizes. Their purpose is to provide a larger supply of water from which to draw. In addition, they ease the burden on the submersible, since it can be controlled to fill the tank at a different time, or during a longer period, than when the water is being used. For instance, with a marginal well, where the well’s output is insufficient to meet peak demand, a storage tank can be filled steadily at a slow rate, and the water withdrawn from storage at a high rate when needed. This strategy maximizes the water production of the well. Another benefit is that stored water is available should the well be disabled for any reason. And, if necessary, water can be delivered from an outside source and stored in the tank.

Storage tanks are occasionally placed at a high elevation. The submersible pump fills the tank, and gravity alone provides water pressure for the house. For example, if the storage tank is 100 feet higher than the house, then the water pressure at the house will be about 43 pounds per square inch (PSI). Since most properties don’t have a sufficiently elevated tank location, the water pressure is instead provided by a separate pressure (jet) pump. The submersible pump fills the storage tank (controlled by a liquid level control in the tank), and the pressure pump (controlled by a pressure switch) fills the pressure tank.

Storage tanks in this area are often plastic, above-ground models. Popular sizes are 1500 and 2500 gallons. These units are long-lasting, relatively inexpensive, and easy to transport to difficult locations. They require about an eight foot diameter space, which need only be flat and rock free. Buried tanks are also available.

These are generally used in the aforementioned two-pump systems. A typical setup is as follows: the submersible pump fills a storage tank, and the water from the storage tank is pressurized by the second (jet) pump. A pressure tank is also used so that the jet pump only cycles occasionally. Jet pumps come in many sizes, half-horsepower being a popular choice for a small residential system. Installation location varies. The jet pump is often mounted on top of the pressure tank, other times in a separate location, but usually outside of the living space, since the pump does make some noise. Constant pressure systems are also available. These systems require only a small pressure tank, and the pump itself may be located inside the storage tank, or even down the well in a single pump setup.

Most installations use grid (utility company) power. But since we’re in a rural area where grid power is sometimes distant or expensive, it’s not uncommon for homes to be powered by generators, solar, or wind power. Most solar/wind installations consist of solar panels and/or wind turbines to supply the energy, batteries to store the energy, and inverters to convert the battery (DC) power to home power (AC). Most systems include an engine-driven backup generator (fueled with gas, diesel, or propane), to keep the batteries charged when there’s no sun or wind. The combinations of equipment and their use are highly variable, but here are the most common:

• The home is equipped with a solar and/or wind power system. The water system is powered by the same power system. This setup is used when water requirements are modest, or the power system is a larger size.
• The home is equipped with a solar and/or wind system. But the water system, and possibly other large loads, are powered by a separate engine-driven generator. This setup is used when the home power system is too small to run the water system because the water is too deep and/or the water demand is higher.
•  The home and water system are both powered by generator only.
•  The home and water system each use a separate solar or wind power system.

We’re often asked: “Which off-grid system should I use?” The answer is always the same: “It depends”. Here are just a few of the elements which play a part — water depth, water use, size of your intended power system, your home energy use, whether you mind running a generator, and, of course, your budget. Please call us if we can provide some advice

Most residential water systems require very little maintenance, but there are a few things worth keeping an eye on.

Water quality – Well water should be checked occasionally for bacterial contaminants. You can take a sample yourself and have it lab-tested, or you can use a less expensive field test kit (we keep these in stock, and can do the test for you) There’s seldom a problem unless the well is near a septic system or contamination from animal sources. Occasionally residential wells are also tested for industrial contaminants, etc.

Storage tanks – Take a look inside occasionally to check for sediment building up on the bottom. Excess sediment can end up in your household plumbing, or harbor bacteria in the tank.

Electrical controls – Repair any damage to shelters which might allow water or rodents into controls. A common problem is ants fouling the contacts in pressure switches.

Pressure tanks – These are maintenance free, but you can prolong their life by keeping them out of the hot sun if possible.

Well head, surface plumbing – Promptly repair any physical damage caused by animals chewing on components or insulation, etc. Fence off the area if necessary. Keep above-ground plastic plumbing shielded from the sun. Check your entire installation before winter to see that insulation is adequate. Marginal wells should have draw-down tests performed occasionally to verify that control timers, etc., are set up properly and functioning. Valves should be operated occasionally to prevent them from becoming stuck in position, especially if the mineral content of the water is high.

Off- grid power systems – Keep insects out of inverters and controls. Keep vents clear of dust and debris. Check batteries often for proper water-level and verify that connections are clean and tight. Prevent batteries from being exposed to freezing temperatures, especially when charge levels are low. If powered by an engine-driven generator, don’t let the generator run out of fuel while the well pump is operating. Check occasionally for proper voltage output.

General advice – Know your system. It’s best to be familiar with the sounds and cycle times of the components. This way you’ll recognize symptoms early, such as too-rapid cycling of pumps. Be sure the system is equipped with a pump saver device if there’s any possibility of low water or faulty electrical supply.

Properly installed and maintained systems generally perform well for many years. But here are the most common problems, and their causes.

Early submersible failure –  Pumps sometimes fail early if they’ve been sized incorrectly, or have been pumping excessive contaminants. Motors can fail early if they’ve been subjected to poor power supply, such as inadequate wiring or fusing, or being repeatedly allowed to run at low voltage as the generator runs out of fuel. Running the pump dry will also cause premature failure. This can happen if the pump electrical controls are inadequate for use on a marginal well.

Pressure tank failure – Pressure tanks often last a very long time, but occasionally they can be short-lived. The average lifespan is probably about five years. Fewer operating cycles equals longer life, so the tank should be sized to minimize cycling. When pressure tanks fail, the submersible or pressure pump will be cycling much more rapidly than normal, which can in turn cause the pumps to fail as well.

Freezing – Above ground plumbing is subject to occasional freezing, even in our warm climate. Most problems with frozen pipes cure themselves once it warms up. But pipes and valves can split when frozen, resulting in floods when the components thaw out, occasionally causing pumps to run endlessly and fail as a result.

Well drilling is a complicated operation, so what follows is only a general description of the process. In our area, where water is usually deep down in solid material, most wells are drilled with a rotary-pneumatic drill rig. The drill shaft rotates, and the cutting head hammers away at the rock. Cuttings are flushed to the surface with air or water. The machine used to bore the hole is mounted on a large truck, and has a tall mast to accommodate the drill string. In addition to the drill rig, there may also be additional large trucks to supply water and carry drill pipe, so it’s desirable to have plenty of space at the drill site for all this equipment. After drilling the hole, a casing (usually PVC) is installed to line the entire depth of the hole, and a length of larger, steel casing is added at the surface. The steel part is grouted (cemented) in place, to prevent contaminants from running down alongside the casing. When the well is complete, all you can see is about two feet of this steel casing protruding from the ground, with a little cement surrounding the pipe.

The choice of a specific location for your well will depend on many factors, including ease of access, distance to power supply, etc. The best estimate of depth is likely to be based on the depths of nearby wells. Give us a call, we’ve probably worked on wells in your area. You can also search online or by phone/fax for details about neighboring wells.