{"id":2080,"date":"2026-10-13T17:21:00","date_gmt":"2026-10-13T09:21:00","guid":{"rendered":"https:\/\/borrapumps.com\/blog\/deep-well-pump-head-calculation\/"},"modified":"2026-10-11T17:13:39","modified_gmt":"2026-10-11T09:13:39","slug":"deep-well-pump-head-calculation","status":"publish","type":"post","link":"https:\/\/borrapumps.com\/es\/blog\/deep-well-pump-head-calculation\/","title":{"rendered":"Deep Well Pump Head Calculation: Static and Dynamic Water Level"},"content":{"rendered":"

Deep well pump head calculation should use the pumping water level, the delivery elevation, the required outlet pressure and losses through the complete discharge route. Do not use total borehole depth as the static lift, and do not select a pump from the water level measured before pumping alone. A submersible pump’s setting depth matters for installation, submergence and pipe length, but the static elevation term normally starts at the well’s operating water surface. Keep flow and head together when reviewing the configuration-specific curve, and calculate more than one water-level condition where the well varies.<\/p>\n

Separate the well dimensions before calculating<\/h2>\n

Record the well reference point, total depth, static water level, pumping water level and proposed pump setting. Use one consistent datum. A level reported as a distance below the top of casing cannot be combined directly with an elevation referenced to a different ground point. Record the casing reference height so the designer can translate all measurements into the same system.<\/p>\n

Static water level is measured when the well is not being pumped under the stated conditions. Pumping, or dynamic, water level is measured while a stated flow is being extracted. Drawdown is the difference between those levels for the observed test. The well may respond differently at another flow or after a longer pumping period, so one early reading is not a reliable worst-case operating level.<\/p>\n

The US Department of Energy pump systems resources<\/a> support evaluating the complete pumping system rather than the motor alone. For project inputs, obtain a documented pumping test rather than treating a general regional water-table description as your well\u2019s measured behavior. Also distinguish the well\u2019s sustainable supply from the pump\u2019s potential capacity.<\/p>\n

Measure pumping level at the intended flow<\/h2>\n

A useful test records flow, time, water level and the measurement reference. Include the starting static level, the level during pumping and recovery after stopping. Use qualified well personnel and an appropriate measurement procedure; do not open energized equipment or lower unapproved instruments near cables and moving parts. Establish the conditions under which the test result applies.<\/p>\n

Penn State Extension’s Before You Drill a Well<\/a> describes recording water level during a pump test. The practical implication is to retain the time series, not just a final number. Ask whether the level stabilized, how long the test ran and whether the discharge rate was maintained. An inconsistent test should be resolved before it becomes a design input.<\/p>\n

Review seasonal conditions and nearby abstraction where relevant. A test during a wet period may not represent the lowest operating level. The designer should establish credible minimum and maximum operating water-level cases using site evidence. Avoid inventing a standard drawdown allowance or applying another well’s behavior because the boreholes have similar depth.<\/p>\n

Build the head equation with defined endpoints<\/h2>\n

For water transferred from a well with an atmospheric free surface to a defined delivery point, a general energy balance can be written as H = \u0394z + \u0394p\/(\u03c1g) + \u0394(v\u00b2)\/(2g) + hL. Here H is required pump head, \u0394z is the endpoint elevation difference, \u0394p is the endpoint pressure difference, \u03c1 is liquid density, g is gravitational acceleration, the velocity term reflects the defined endpoint velocities, and hL represents the route’s friction and local losses.<\/p>\n

Choose endpoints before inserting values. For discharge into an open tank with negligible free-surface velocity, the pressure difference and free-surface velocity terms are commonly zero under those assumptions. For delivery to a pressurized irrigation connection, include the required pressure at that connection. Do not add tank pressure if the destination is actually vented to atmosphere.<\/p>\n

The elevation difference uses the operating water surface and destination elevation. Pump setting depth is not a separate static-lift term to add again. However, the rising main from the installed pump to the surface contributes pipe length and therefore losses. A deeper setting can increase those losses even though setting depth itself is not the water-surface lift.<\/p>\n

Use a transparent illustrative calculation<\/h2>\n

Consider an assumed well whose pumping water surface is 55 m below the common ground datum at the selected flow. The delivery connection is 8 m above that datum, requires 2.0 bar gauge pressure, and has an assumed 9 m of total route losses at that flow. Assume water density of 1,000 kg\/m\u00b3, gravitational acceleration of 9.80665 m\/s\u00b2 and negligible endpoint velocity-head difference. These are example inputs, not BorraPumps performance data.<\/p>\n

The elevation term is 55 + 8 = 63 m. The pressure term is 200,000\/(1,000 \u00d7 9.80665) = approximately 20.39 m. Required head is therefore 63 + 20.39 + 9 = approximately 92.4 m at the stated flow. Specify that flow beside the head; a head value alone does not identify a suitable pump.<\/p>\n

If the same well initially had a static water level 45 m below ground, using that level would produce about 82.4 m with the same other inputs. That calculation understates the example’s pumping condition by 10 m. If the pump were set at 85 m below ground, adding 85 m as another static term would also be wrong: account for the setting in installation requirements and actual pipe losses instead.<\/p>\n

Keep the calculation inputs in one table<\/h2>\n

This table documents the illustrative calculation and identifies what must replace each assumption in a real project. It is not a selection chart for any particular model.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
Input or term<\/th>\nIllustrative value<\/th>\nContribution<\/th>\nProject evidence needed<\/th>\n<\/tr>\n<\/thead>\n
Pumping water level below datum<\/td>\n55 m<\/td>\nPart of elevation difference<\/td>\nTest level at stated flow and time<\/td>\n<\/tr>\n
Delivery elevation above datum<\/td>\n8 m<\/td>\nTotal elevation difference becomes 63 m<\/td>\nSurvey using the same datum<\/td>\n<\/tr>\n
Required delivery pressure<\/td>\n2.0 bar gauge<\/td>\nApproximately 20.39 m for assumed water density<\/td>\nDemand specification at defined connection<\/td>\n<\/tr>\n
Route losses<\/td>\n9 m at selected flow<\/td>\nAdd 9 m<\/td>\nPipe dimensions, length and fitting calculation<\/td>\n<\/tr>\n
Endpoint velocity-head difference<\/td>\nAssumed negligible<\/td>\nZero in this example<\/td>\nVerify endpoint definitions and velocities<\/td>\n<\/tr>\n
Required pump head<\/td>\nApproximately 92.4 m<\/td>\nEvaluate with the stated flow<\/td>\nActual configuration and speed curve<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Calculate route losses from the complete installed path<\/h2>\n

Include the rising main, surface pipeline, fittings, check valves and other components between the defined endpoints. Record internal diameter, material or applicable roughness assumption, route length and flow. Use a recognized calculation method consistently, and retain component loss data. A short surface distance does not mean a short discharge route when the rising main is long.<\/p>\n

Account for filters or other devices under their relevant operating condition. If pressure demand is specified downstream of a component, include that component’s loss upstream. Avoid counting the same requirement twice as both a device loss and a delivery-pressure allowance. Show where each pressure requirement applies on the route diagram.<\/p>\n

Losses vary with flow and configuration. Recalculate them for the intended duty and credible alternative operating cases. Do not add an arbitrary percentage to compensate for missing pipe data; obtain the missing dimensions or label the preliminary result as an estimate. Distinguish conservative documented assumptions from unsupported oversized motor selection.<\/p>\n

Review operating cases on the actual pump curve<\/h2>\n

Prepare a duty table covering the credible water-level range, delivery-pressure range and required flows. At a lower pumping water surface, elevation head increases. At a higher water surface, the system may require less head and the operating flow can change. Check both conditions against the configuration-specific curve and permissible operating range.<\/p>\n

Use the duty point calculation guide<\/a> for the curve intersection and the deep well pump selection guide<\/a> for the wider procurement requirements. The focused head calculation here supplies one important input; it does not establish well yield, motor suitability, diameter clearance or acceptable water quality by itself.<\/p>\n

The BorraPumps QJ deep well pump product family<\/a> provides a relevant equipment reference. Ask for the offered assembly’s curve, stage configuration, operating limits and approved installation requirements. Do not infer a particular head, flow or stage count from the product photograph or the family name.<\/p>\n

\"Exterior
Verify actual intake location and required submergence using the selected model\u2019s installation documents.<\/figcaption><\/figure>\n

Keep setting depth and protection in the installation review<\/h2>\n

Determine the pump intake position, required submergence, motor cooling arrangement and clearances using the selected model’s instructions and well construction. The intake must remain suitable for the credible pumping-level conditions, while the installation must also avoid unsuitable placement or unverified sediment exposure. There is no universal setting offset that can safely replace this review.<\/p>\n

Coordinate dry-running protection, level sensing and control behavior with the well’s supply. Check cable, electrical protection, rising-main pressure capability and safe lifting arrangements separately. For irrigation demand planning, use the deep well irrigation sizing guide<\/a>. Keep these checks connected to the calculation without hiding them inside an unexplained head allowance.<\/p>\n

\"Reference
Keep the site datum, pumping test and route assumptions with the calculation record.<\/figcaption><\/figure>\n

Verify the installed duty and retain the assumptions<\/h2>\n

During commissioning, measure delivered flow, pressure and pumping water level under stated conditions. Compare them with the calculation and curve, using consistent units and measurement locations. Investigate differences in level, loss estimates, valve conditions or measurement methods before assuming that the pump is defective.<\/p>\n

Keep the calculation revision with the final pipeline record and test results. Later changes to pressure demand, filters, route or well behavior should trigger a review of the relevant terms. A reproducible calculation makes that review faster and gives the operating team a defensible baseline for declining flow or rising energy demand.<\/p>\n

Further learning<\/h2>\n

Practical Engineering explains how flow, pressure and system resistance interact. The lesson supports understanding the operating point; it does not replace the documented well test or the specific head calculation.<\/p>\n