Well production balance worksheet

Account for the water before blaming the well

When a plant, housing project or farm complains that “the borewell is giving less water”, the first instinct is often to call for a new pump, a deeper bore or well cleaning. Sometimes that is right. Often the shortfall is somewhere else: a tank overflow, a leaking transfer line, a meter that rolled over, or a pump that ran for eight hours but delivered for only six because of air locking or low water level.

The worksheet on this page keeps production, delivery and storage separate so ordinary operating effects are not mistaken for well performance. Its most useful output is not a single percentage but a clear statement of what is accounted for, what is not, and which evidence is needed next.

The balance equation

For one physical boundary and one time interval:

Residual = well production + other inflows − deliveries − other known outflows − change in storage

where change in storage is closing volume minus opening volume. A residual close to zero means the account closes. A positive residual means more water entered than can be accounted for leaving or being stored; a negative residual means more water appears to have left or been stored than entered. Either way, the residual is an investigation item, not proof of a leak or a meter fault.

Inputs and evidence

Step-by-step method

1. Draw the boundary. Decide exactly what is inside: one well and its tank, or several wells, tanks and transfer pumps.
2. Fix one clock. Use the same start and end times for every reading; a tank dip taken an hour after the meter reading distorts the account.
3. Calculate meter volumes. Subtract opening from closing totaliser readings, and check for rollovers, resets or replaced meters.
4. Use real producing hours. Separate hours the motor was energised from hours water was actually delivered.
5. Convert tank levels to volume. Use the level–volume relation for the actual tank shape, not just height × area if the tank is not a simple cylinder or box.
6. Calculate the residual and express it in m³ and as a share of total inflow.
7. Investigate where the difference first appears, starting with the cheapest checks: meter readings, tank levels, visible leaks and overflows.
8. Issue the account with every number’s status (measured, estimated or missing) so the next shift can continue it.

Worked example A: a daily balance with storage gain

Illustrative figures only. The well totaliser rises from 12,450 to 12,546 m³ over 24 hours, so production is 96 m³. A tanker adds 12 m³. Metered delivery to the process is 88 m³ and recorded flushing is 5 m³. The tank rises from 30 to 43 m³.

Residual = 96 + 12 − 88 − 5 − 13 = +2 m³, about 1.9% of total inflow. The correct statement is “2 m³ unexplained”, not “2 m³ leaked”.

Worked example B: power-on time is not water time

In a ten-hour window the pump delivers for six hours at 12 m³/h and two hours at 9 m³/h, runs for half an hour with no delivery because the water level has dropped to the pump, and is stopped for 1.5 hours. Supported production is (12 × 6) + (9 × 2) = 90 m³. Multiplying 8.5 energised hours by 12 m³/h gives 102 m³, and ten hours gives 120 m³; both overstate production. Dry running is also a warning sign for the pump itself and for the well’s sustainable yield.

Worked example C: two wells and a falling tank

Well A gives 60 m³ and well B 45 m³ into tank A, which opens at 40 m³, transfers 110 m³ to tank B, loses 5 m³ to a documented drain and closes at 30 m³: 40 + 105 − 110 − 5 = 30, so it closes. Tank B opens at 20 m³, receives 110 m³ plus 15 m³ from an outside source, delivers 140 m³ and closes at 5 m³: 20 + 110 + 15 − 140 = 5. Across the site, storage fell by 25 m³. Delivery that day exceeded well production because stored water was drawn down and 15 m³ came from outside, not because a meter was wrong.

Reading the results

Limits

A balanced account shows where the water went. It does not prove the well’s sustainable yield, interpret a pumping test or justify pumping more. Do not force a residual to zero by adjusting a reading, and do not treat an incomplete period as complete. Yield and aquifer questions need proper testing and, where required, the relevant groundwater authority’s rules.

Keeping the record useful over time

A single day’s balance is useful; a continuous record is far more valuable. Keep the worksheet running daily or by shift, with the same boundary and the same reading times, and add a short note whenever something changes: a meter replaced, a new tank connected, a pump reset to a different depth or a well cleaned. Over a season the record shows whether production falls with the water table, whether losses are growing, and whether cleaning or pump work actually restored output.

Take a static water level reading before the pump starts and a pumping level after it has run steadily, where an access tube or dipper allows it. Those two readings, kept alongside production, are the simplest evidence for telling a tired pump from a well that is losing yield.

How Reddy Compressors helps

Reddy Compressors supplies all types, all brands and all models of borewell compressors: new sales, used and refurbished machines, rentals, service and spare parts. We work with drilling contractors, rig owners, farms, real-estate developers and industrial sites across Telangana and Andhra Pradesh from our office at Tarnaka, Secunderabad, and supply compressors and spares across India.

When a production balance shows a well is genuinely losing yield because of clogging, silt or poor development, compressed-air well cleaning and airlift development are often part of the remedy. We can supply or hire a borewell compressor at the right pressure, typically 600–1,500 cfm at 200–400 psig (13.8–27.6 bar) with special units up to 35 bar (507.6 psig), and service teams to support it. We are an independent multi-brand specialist, not an authorised dealer of any brand. We have tie-ups with all major and reputed brands.

What to send us

• Well depth, casing diameter and the date it was drilled, if known.
• Recent production records: meter readings, run hours, tank levels.
• Your concern: falling yield, sand, dry running or unexplained losses.
• Site location and access for a compressor and rig.
• Whether you need a compressor for cleaning, development or new drilling.

Frequently asked questions

Is pump running time enough to calculate borewell production?

No. A pump can be energised while delivering little or no water, for example when the water level falls to the pump intake or the line is air-locked. Multiplying run hours by a nominal flow rate overstates production. Use a flow totaliser at the wellhead where possible, or record the hours water was actually delivered at each confirmed flow rate.

Why can tank delivery be more than the water the well produced today?

Because stored water from earlier days can be drawn down. If the tank level falls during the day, the extra delivery came from storage, not from the well. The worksheet records opening and closing tank volumes so that a drawdown is shown as a storage change, and does not appear as a meter error or as extra production.

Does a positive residual in the water balance prove there is a leak?

No. It means more water entered the boundary than can be accounted for. A leak is one possible cause, but so are tank overflows, unmetered taps, meter error, an incorrect tank level–volume table or readings taken at different times. Walk the system, check meters and timings, and only then attribute the difference to leakage.

Why is my borewell giving less water than before?

Common causes include a seasonal fall in the water table, a worn or wrongly set pump, a clogged screen or fractures, sand and silt build-up, or new wells nearby. First confirm the shortfall with a production balance, then check water levels and the pump. Where clogging or silting is likely, compressed-air well cleaning and development can often restore part of the yield.

What residual percentage is acceptable in a well water balance?

There is no single acceptable figure. It depends on meter accuracy, how tank levels are measured and how readings are timed. A small, steady residual that stays within the combined uncertainty of your meters is usually acceptable. A residual that grows, changes sign or jumps suddenly deserves investigation even if it looks small as a percentage.

Can a compressor be used to clean a borewell?

Yes. Compressed air is widely used to clean and develop borewells by airlifting water, silt and sand out of the bore, and to clear blocked fractures. The compressor’s pressure must overcome the water column above the air line, so deeper wells need higher pressure. We supply and hire borewell compressors for this work and can advise on the right size.

Related pages

• Borewell and DTH compressor library
• Well completion, cleaning and development
• Borewell yield testing and production duty
• Borewell compressor rentals and hire
• Forecast variance and production control
• Pumping test data screening worksheet