This article describes Well Pits to Contain Water Equipment & Well Access. We provide advice about what to do when things go wrong.

We discuss: Types of wells and water supply systems and what to watch out for with each.

What sorts of problems occur at well pits? Well pump & water tank well pit-well diagnosis & repair procedures.

Well Pits for Access to Well Heads, Pressure Tanks, Pumps, Controls

What is a Well Pit & Why are Well Pits Used - sketch & explanation

Well Pits for drilled wells are excavations, usually outdoors, which were dug below to below the frost line (in freezing climates) to house the well top and sometimes the pump and water tank.

Well pits are an older approach to well construction in climates subject to freezing, in which a well pit was dug to place piping and controls below the frost line.

Newer drilled wells extend the casing above ground and use a pitless adapter if the well is in a freezing climate.

The photo above shows a messy well pit interior with a plastic bucket over a well casing and a glimpse of the water pressure tank. At page top we have a collapsing well pit with no cover whatsoever - a serious falling hazard.

The sketch shown above, courtesy of Carson Dunlop Associates, demonstrates use of a well pit of capping and accessing drilled wells was used in order to provide ready access to the equipment while also assuring that the water line between the well and the building it serves was protected from frost.

While the sketch places the water pump and pressure tank inside the building, in many instances the well pit may contain all of these items.

Below is a photo of an ugly well pit with a bucket covering the well head - what does that tell us?

Well pits are very common in many areas all over the world.

Well Pit or Well Vault Construction Standards:

Current standards recommend against constructing a well pit, substituting a pitless adapter instead.

Well Pits or Vaults.

The use of well pits, vaults, or equivalent features to house the top of a well casing below ground surface shall be avoided, if possible, because of their susceptibility to the entrance of poor-quality water, contaminants and pollutants.

Our photo of a concrete well pit was contributed by reader Rees in a question and answer posted originally

at WELL CHLORINATION & DISINFECTION (12/2017)

Well pits or vaults can only be used if approval is obtained from the enforcing agency.

A substitute device, such as a pitless adapter or pitless adapter unit (a variation), should almost always be used in place of a vault or pit. - California DWR Chapter 10, 2016 cited below- California DWR Chapter 10, 2016 cited atReferences or Citations below

Pitless adapters and units were developed for use in areas where prolonged freezing occurs, and below ground (frost line) discharges are common.

Both the National Sanitation Foundation and Water Systems Council have developed standards for the manufacture and installation of pitless adapters and units. (See Appendix E, Bibliography, Bulletin 74-81.)

If a pit or vault is used it shall be watertight and structurally sound. The vault shall extend from the top of the annular seal to at least ground surface.

The vault shall contact the annular seal in a manner to form a watertight and structurally sound connection.

Contacts between the vault and the annular seal, and the vault and the well casing, if any, shall not fail or cause the failure of the well casing or annular seal.

Where cement-based annular seal materials are used, the vault shall be set into or contact the annular seal material before it sets, unless otherwise approved by the enforcing agency

. If bentonite-based sealing material is used for the annular seal, the vault should be set into the bentonite before it is fully hydrated.

Cement-based sealing material shall be placed between the outer walls of the vault and the excavation into which it is placed to form a proper, structurally sound foundation for the vault, and to seal the space between the vault and excavation.

The sealing material surrounding a vault shall extend from the top of the annular seal to ground surface unless precluded in areas of freezing.

If cement-based sealing material is used for both the annular seal and the space between the excavation and vault, the sealing material shall be emplaced in a 'continuous pour'.

In other words, cement-based sealing material shall be placed between the vault and excavation and contact the cement-based annular seal before the annular seal has set.

The vault cover or lid shall be watertight but shall allow the venting of gases. The lid shall be fitted with a security device to prevent unauthorized access. The outside of the lid shall be clearly and permanently labeled 'WATER WELL'.

The vault and its lid shall be strong enough to support vehicular traffic where such traffic might occur.

The top of the vault shall be set at, or above, grade so that drainage is away from the vault.

The top of the well casing contained within the vault shall be covered in accordance with requirements under Subsection A, above, so that water, contaminants, and pollutants that may enter the vault will not enter the well casing.

The cover shall be provided with a pressure relief or venting device for gases.

Watch out: Safety Warnings Regarding Well Pits

• Well pit covers: As with our concern for dug well safety, a well pit should have a child-safe cover to prevent falling-in and injury.


• Well Pit shock hazards: You should also be very careful of electrical shock hazards when entering a well pit. Often the well pit is wet or perhaps even flooded. In such cases be sure to turn off electrical power before entering in or working in the well pit.
  
  At a property where we broke a water supply fitting we needed to shut off the water pump.
  
  The water pump and its controls were in an outside well pit. On opening the pit cover and seeing a foot of water therein we knew better than to jump down into the pit to turn off the pump switch.
  
  We used a dry broomstick to push the switch to the off position. We could also have found the main electrical panel and found and turned off the pump circuit there.


• Watch for collapsing well pits such as the frost-damaged masonry block pit walls shown at page top.

As we also discuss

at DUG WELLS, by HAND,

our photo illustrates a hand dug well that was converted to a drilled well with a steel casing.

The old hand-dug well now serves as a well pit. Notice that there is no protection against surface runoff entering the top of the well casing - a sanitary or water potability concern. This rural well is being used for crop watering in San Miguel de Allende.

• Watch out for flooding well pits - especially if the well cap is located in the well pit floor. A well pit that floods risks leaking unsanitary surface water into the well - be sure that the well cap is water tight in these cases, and take steps to keep water out of the well pit.
  
  At a property inspection we observed a well pit housing the well head itself as well as water pump and pressure tank. The well casing had no cover installed. It was raining.
  
  Water was running across the property from a pony stable down into the well pit and into the well.
  
  Manure-runoff was entering the drinking supply, making it unsanitary and possibly quite dangerous to the building occupants. The well needed to be sterilized, tested, and provided with a water-tight sanitary cover.
  
  The well pit needed to be protected from surface runoff from the stables. The building occupants needed to be informed immediately that their water was unsanitary.

A rough sketch of a well pit and a compression-type well sealing cap can also be seen

at WATER PUMP, TWO LINE JET

or select a topic from closely-related articles below, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2021-03-27 by (mod) - how to connect PEX to older galvanized or copper piping systems for water supply

Please find your question and our detailed reply along with your own photos and description of the actual well piping repair procedures you used, now at

WELL PIPING REPAIRS

On 2021-03-27 by Paul - need to replace galvanzed well piping: what connectors can I use?

Our well pit water system was replaced 40-50 years ago with a metal-case pitless system, which was placed inside of the now back-filled, circular, concrete-wall well pit

. The original (i.e., "pre-pitless") 3/4-inch galvanized service line into the basement of the house needs replacing, as it is leaking, and will not hold pressure.

That service line pipe is a little over 20 feet long, and we plan to hand dig and replace it with PEX ourselves.

What kind of connector can I expect to find for connecting the new PEX line to the pitless pump? Would the installer have extended the pitless adaptor to the outside of the poured concrete pit wall, to make it easily-accessible (i.e. OUTside of the pit) for the then-distant future, yet imminent, service line replacement? If not, then what can I expect?

On 2020-10-09 by Steve

Thank you so much for your time and guidance. Take care and be well

On 2020-10-09 - by (mod) -

Steve

I'd start by keeping water away from and out of the well pit; else we risk electrical issues, sanitation issues, wet insulation, well contamination, inability to access components in the well pit in some weather conditions;

Foaming the well cap might cause trouble if your well cap is vented. If the well cap isn't vented then it's a stopgap pending replacement of the well cap with one using an effective seal.

I'm ok with using foam to slow down leaks in a wall but it's a band-aid, not a fix.

On 2020-10-09 by Steve

Sorry they're typos. I have 5 stage RO treatment for cooking and drinking water.

Thanks for your speedy response. My well pit was retaining water during heavy rain. It's not brick, it's two foot+ wide and deep perforated ridge pipe with dirt at the bottom . I would say it's about 2- 3 ft below ground total with a cement cover a few inches blow the grass. It has a cast iron new cap (not vented) and pump. When I exposed it there was insulation in the pit (typical house insulation).

I was wondering if I can just use the big gap filler and foam the entire pit out. This way it would fill the void and restrict water from accumulating above and around the cap.

I know it'll make it difficult to access. But it's easy just to cut it out if need be. Ideally I should have raised the pipe above ground and put a modern vented cap.

Do you see any major issues with the foam for a temporary solution. I guess besides the breathing or venting issue. like I said there's no vent now it's a sealed type of cap with the wires and the water intake line .

Supposedly it's inert once it dries The well is a hundred feet deep and I have oral treatment system in the house for drinking water.
Thanks so much.

On 2020-10-09 by (mod) - use foam to insulate the well pit?

Steve

Forgive me - what problem are we solving here? If you want to use some foam to seal gaps in concrete blocks forming a well pit wall, that's harmless, but I'd warn that the forces that push in concrete block walls around a well pit will not be deterred one iota by the insulation.

On 2020-10-09 by Steve

Hello, can a insolation product such as the inert drying inert foams like big gap sealer etc, be used to fill and insolate the well pit if you have a good sealed well cap? Thanks

On 2019-01-08 by (mod) - seal the concrete at the well casing

I would clean the surfaces involved and use first a silicone or other sticky sealant; you may not get a perfect and durable outdoor seal with just concrete against steel.

Watch out: if surface runoff is also passing around our well vault well crypt well pit and beneath it, just sealing the casing inside the well pit at the pit floor won't prevent that other water from passing down the casing - IF - in fact the casing's original seal is defective.

It would make sense to have your well water tested for bacteria.

On 2019-01-08 by Rees

So it isn't sealed. A ring of concrete around the well casing at the floor level?

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Continue reading at PITLESS ADAPTERS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see WELL PIT FAQs - questions and answers posted originally on this page

Or see these

Recommended Articles

• PIPE FREEZE-UP POINTS - where water suppy systems tend to freeze-up
• PITLESS ADAPTERS
• WATER PRESSURE LOSS DIAGNOSIS & REPAIR
• WATER TANK LOCATION GUIDE
• WELL CAPS & COVERS safety and sealing requirements
• WELL CASING LEAK REPAIRS
• WELL PIPING REPAIRS
• WELL RINGS: WHEN TO USE or OMIT

Suggested citation for this web page

WELL PITS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

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