Photograph of a sketch of the main controls and valves on a water systemWater Pump Controls
A Photo-Guide & Dictionary of Water Pump & Well Controls & Switches

  • POST a QUESTION or READ FAQs about how to troubleshoot problems with water pump controls, how to repair or replace pump controls such as pressure control switches, check valves, foot valves, and air volume controls

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Well Pump & Water Pump Controls:

This article describes and identifies the switches, controls, and safety devices used on water tanks and water pumps such as the pump pressure control switch, pump motor relays, water tank relief valve, water tank pressure gauge, water tank air volume control, and water tank air valve.

We discuss these well or water pump control questions: What are the functions of the well water pump pressure control switch, water tank relief valve, water tank gauge, water pump relays, water tank valves. Well pump & water tank diagnosis & repair procedures.

A Dictionary of Water Pump & Water Tank Controls, Switches, & Attachments

Photograph of a water pressure tank air valveThis article uses sketches and photographs to assist in locating and identifying all of the controls and switches found on residential water supply systems including the well, water pressure tank, water pump, and their associated valves and devices.

We also provide maintenance and repair and emergency water shutoff tips throughout these descriptions.

How to Identify Water Well, Pump, & Tank Components & Switches

In addition to the individual well, pump, and tank component photographs provided in the article below, our photograph at left has a number easy-to-identify water system components that happen to all be in one place:

Guide to Identification of the Water System Components Shown in the Page Top Sketch

Photo of a water tank air valve for adding air to a water pressure tankThe page top sketch is expanded by detailed photographs as we explain each of the components and controls of wells, pumps, and water tanks. In our sketch (sorry the author is a technician but not an artist), you can identify the basic components of a private well system (listed next) but as you'll see in our detailed articles and photos which follow, these components are not always located where they're as easy to spot and name as in our drawing.

Air valve (Label #7 in the page top sketch and shown in the photo at left) or "Schrader valve" (looks like a tire valve). The water tank air valve shown in this photo is one that you should not normally have to use as it's installed on a captive air or bladder type water tank.

On water tanks that do not use an internal bladder, the air valve, or Schrader valve, used to add air to the water tank can be seen in this photo.

Details are at TANK AIR INLET VALVE.

At WATER TANK AIR, HOW TO ADD we discuss adding the right amount of air to a non-bladder steel or glass-lined well tank.

And at WATER TANK BLADDER PRESSURE ADJUSTMENT we discuss fine tuning the pump pressure control switch to work perfectly with the exact air pressure pre-charge in a bladder type well tank.

Air volume control (Label #6) and copper or plastic tube connecting the AVC to the water pump or a fitting nearby.

Photo of a water tank air volume control

An air volume control valve or device is not presentOn "captive air" bladder type water tanks - this control can take several appearances.

Here is a photo of a different type of water tank air volume control.

Details on using and repairing water tank air volume controls are


Check Valves on water piping, well pumps, wells. Shown below.

Water piping check valve (C) Daniel Friedman

Check valves prevent back-flow of water through piping for any of several reasons such as preventing loss of well pump prime by a check valve located at an above-ground water pump or at the water pressure tank -


Electrical Power (Labeled SW in the sketch at page top) - Electrical switch at the water pump.


Foot valve on well piping (C) Daniel Friedman

Foot Valves on well piping are located on the bottom of the well piping, inside the water well. The foot valve helps prevent loss of prime in the well pump and piping system when the pump stops running -


Photograph of a well water tank pressure gauge
Gauge (Label #3) - Water tank pressure gauge. The water pressure gauge on home water systems is one of the most helpful and simple devices used in diagnosing poor water pressure and pump, well, or pump control problems.

This gauge has broken cover and needs replacement.

See WATER TANK PRESSURE GAUGE for water pressure gauge explanation and repair advice.

We discuss gauge problems with air or water pressure gauge readings on water tanks


Piping (Labeled "from pump & well" at left) - Well piping bringing water from the well to the water pressure tank and building.


Piping (Labeled "to house fixtures" at right )- Building water supply piping a main water line leaving the water pressure tank and bringing water to the building and its fixtures.



Pitless Adapter (shown in sketch below): the pitless adapter provides a water-tight connection that permits the well piping to pass out through the side of a round steel well casing.

Pitless adapter sketch (C) InspectApedia

Our illustration (above left) shows a low-pressure well spool using a clamp-on pitless adapter in a design suitable for artesian wells whose head pressure is equal to or less than 5 psi (a head of 11.5 ft.) - courtesy Michigan DEP.

We illustrate and discuss the use of pitless adapters at PITLESS ADAPTER. Also see

Low Water Cutoff for the Well Pump - Many sources, including the Penn State School of Forest Resources recommend installing a low water cutoff device to protect a well pump that has to operate in an inadequate or low-yield well. That resource describes an electrical low-water cutoff switch.

A low water sensing device to protect a well pump may be installed in an intermediate water storage tank, for example. If your well pump has stopped running and an electric low water cutoff switch is installed you'll want to check that the switch is working properly.

Photo of a one-line jet pump water pump

Details about electric and other low water cutoff devices to protect the well pump from damage are described in detail


Pump- Water pump
either at or close to the water pressure tank or located separately in a well pit (not shown in this sketch) or in the well itself (shown as pump at far center right in sketch at the top of this article ).

The water pump shown in this photo is installed right on top of the water tank and it is easily identified as a "one line jet pump" since we see only a single pipe entering the pump from the well - the black ABS piping coming into the pump from its lower left.

The outlet of this one line jet water pump is the copper pipe at upper right of the blue pump assembly.

If you do not see a water pump anywhere in the building, and if the property does not use an outdoor well pit or well house, then your well water pump is probably a submersible unit.

Details of the different types of water pumps such as one line jet pumps, two line jet pumps and submersible water pumps are described in detail at WATER PUMP TYPES & LIFE EXPECTANCY

Relay Switch - Pump relay
(Drawn as box at right center in sketch) turns on and off a higher-voltage water pump such as some submersible pumps (not present on all water systems).

Photograph of a water pressure tank air valve

The water pump relay switch is a heavy-duty switch that turns on and off a submersible water pump. Some lower ampacity submersible well water pumps may be switched on and off directly by the pump pressure control switch.)
Shown here is a Homart submersible well pump relay switch.

You can see a Gould™ submersible water pump relay switch mounted on the wall in this photograph: WATER TANK (Label #1) [photo]

For details about the water pump relay switch, its use, inspection, and repair,


Relief Valve (Label #2) - pressure relief valve on the water tank.

Water tank relief valves (red arrow in photo) were omitted by lots of plumbers installing pump, tank, and well systems, but most plumbing codes and local codes require a pressure relief valve on any tank which contains something under pressure, including a home water tank.

Photo of a water tank pressure relief valve

Should the water tank rupture, even at fairly low pressures, a bystander could be hurt or even killed.

This actually happened to a plumber in New York state, making pressure relief valve believers out of plumbers in the area. The tank burst, he was killed.


Shutoff (Label #5) - Main water shutoff valve.

A main water shutoff valve, in this case the blue lever labeled "WATER" with white tape is shown to the left of the pressuregauge and pressure tank drain valve in our photograph (white arrow).

Photograph of a water tank shutoff valve

Details about water shutoff valves can be found at MAIN WATER SHUTOFF VALVE

Switch, pressure (Label #4) - Water tank and pump pressure control switch

The well water pump pressure control switch is the "brain" of a home pump and well system, sensing the water pressure in the building and controlling the turn-on (at low pressure or "cut-in" pressure) and turn-off (at high pressure or "pump cut-out" pressure) of the water pump itself.

Photo of a water pump pressure control switchAll home water pumps use some type of pressure control switch to turn the water pump on and off.


The detailed, step by step procedure for inspecting and adjusting the water pressure control switch is discussed in detail


Some well pump pressure control switches incorporate a WATER PUMP PROTECTION SWITCH that may have to be manually re-set.

Tailpiece - in the well: The tailpiece is an extension on the bottom of well piping (blue) in our drawing at left.

Well pump protection tailpiece © D Friedman at

When the well pump's capacity is known to exceed the flow rate of the well, a tail pipe, tail piece, or low water cutoff control is installed to protect the pump from damage such as that caused by well pump cavitation or motor overheating.

Details about this component and about well pump cavitation are


Tank (Label #1) - water tank: The water pressure tank showing air in the upper portion and water in the lower portion of the tank. The water pressure tank in most buildings has the job of smoothing the pressure and flow of delivery of water to the building.

Photo of a well water tank

At a property whose water well has very limited recovery rate or flow rate, the water tank may be larger, or there may be several of them installed.

In this case the water tank is also storing a buffer quantity of water for use in the home so that the poor well delivery rate does not directly affect the occupants in the building.


At WATER TANK AIR, HOW TO ADD we discuss adding the right amount of air to a non-bladder steel or glass-lined well tank.

Photo of a water tank pressure relief valve

Tee (Label #2) - Bronze tee and water tank pressure relief valve (not always present, but a relief valve should always be installed - add one if it's missing.)

In our photo abov e you can see the bronze water tank tee (blue arrow) attached to the bottom of a water tank, and providing a plumbing connection point for a water tank gauge (green arrow), pressure relief valve (red arrow), and a tank drain valve (yellow arrow) all mounted in this photograph.


Detailed descriptions of individual water system parts and controls, valves, switches, pumps, piping, etc., how they work, how to diagnose, repair, or replace them are provided in the remaining chapters of this article and are listed just below.

Readers of this document should also

see WATER PUMP REPAIR GUIDE an specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.

Reader Question: my new water pressure tank came with just a single outlet fitting at the tank bottom - it does not match my old water tank controls and connections - photos of water tank cross unit or "tank tee"

Water tank cross unit or tank tee © D Friedman at Our photo (at left) shows a water tank cross unit installed on a home in Two Harbors MN. This installation lacks an important safety device - a pressure relief valve. The installer told us he sometimes installs the relief valve inside the well to avoid flooding the building - an unsafe practice because

1. you can't see the valve to know that it is leaking and becoming unsafe and

2. in this case he forgot to do so, leaving this system unprotected.

I am replacing a tank with bad bladder with a new bladder tank. Unbeknownst to me, there is some difference in the set up of the 2 tanks.

The existing tank has the source going directly in the tank (with pressure switch and brass valve inline) and the feed or output is from a separate pipe output fitting in the tank, and the pressure gauge is screwed in another fitting of the tank.

The new tank has only 1 connection at the bottom of the tank, with no separate output fitting or gauge fitting.

Directions with new tank outline using a "tank cross unit"? That shows both the source and feed pipes going into the cross unit which has a pressure switch mounted.

No doubt that scenario allows the use of just the single tank connection for both source and feed. I should mention that I have a deep well submersible pump.

Question - can I use my existing set up and adapt to the single connection new tank by merely placing a tee in that single tank connection and running the source in one end and the feed out the other side of the tee with the 3rd branch of course going into the tank? In additon, "if" I can do that, do I then adapt that pressure gauge in the pipe on the feed side of the tee, or just elimnate it?

Hope I was clear enough and will appreciate any feedback. B.C.


From your description I'm guessing that your tank was sold as a "bare" unit - just the water pressure tank. Other tank assemblies include a brass or bronze tee fitting mounted at that single tank inlet port.

The tee, what your instructions call a tank cross unit, incorporates threaded fittings and tappings to accept all of the necessary connections to the water pressure tank: the pressure control switch, pressure relief valve, water inlet from the well, water outlet to the building, a tank drain, and in some cases, a shutoff valve for the line feeding the building.

You can use the new water tank that you have, but you'll need to visit a plumbing supplier to purchase the missing parts.

In our photo at above left as well as in our article above,

at WATER PUMP CONTROLS & SWITCHES you can see photographs of the water pressure tank cross unit or water tank tee we are discussing.

You can most likely move over your existing controls and fittings to the new tank cross unit, though in the case of a pressure relief valve and gauge I'd prefer to use new equipment.


Continue reading at WATER PUMP PRESSURE CONTROL SWITCH or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER PUMP CONTROL SWITCH FAQs questions & answers posted originally at this article

Or see these

Water Pump Control & Switch Articles

Suggested citation for this web page

WATER PUMP CONTROLS & SWITCHES at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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