What is the water table?

The water table is the upper boundary of the saturated zone in unconfined aquifers — the depth below ground surface where soil and rock pores are fully saturated with groundwater. It fluctuates seasonally and in response to pumping.

What is static water level?

Static water level (SWL) is the depth to water in a well when no pumping is occurring, measured from a reference point such as the top of the well casing or ground surface. It reflects the natural water table or potentiometric surface.

What is hydraulic head?

Hydraulic head is the elevation of the water surface in a well relative to a common datum (usually mean sea level). It equals land surface elevation minus depth to water when measuring a water-table aquifer.

How accurate is this calculator?

Accuracy depends entirely on the quality of your field measurements. The formulas themselves are exact given correct inputs. In practice, measurement error of 0.01–0.1 ft is typical for electronic water-level meters.

What units should I use?

All three methods accept either feet or meters — select your preferred unit before entering values. Results are always shown in both units automatically.

What is the hydraulic gradient method?

The hydraulic gradient method interpolates the water table elevation at an intermediate point between two monitoring wells using the linear head difference divided by horizontal distance, then converts back to depth below ground surface.

Water Table Depth Calculator

Name: Water Table Depth Calculator
Availability: InStock
Author: Nham Vu

Calculate depth to the water table from well measurements, surface elevation, or hydraulic head data.

Inputs

Measurement Units

Calculation Method

Top of Casing Elevation above Ground (ft)

Height of casing top above ground surface. Enter 0 if flush with ground.

Static Water Level — depth from casing top (ft)

Enter your measurements and click Calculate.

Summary

Calculate depth to the water table from well measurements, surface elevation, or hydraulic head data.

How it works

Select the calculation method that matches your available data.
Enter the required measurements (depths, elevations, or hydraulic head values).
Click "Calculate" to run the hydrogeology formula instantly.
Review the depth to water table in both feet and meters.
Use the gradient method to interpolate depth at a point between two wells.

Use cases

Estimating groundwater depth before drilling a new well.
Environmental site assessments requiring water table mapping.
Agricultural planning for irrigation and drainage design.
Construction projects needing dewatering depth estimates.
Hydrogeology coursework and field data analysis.
Monitoring seasonal fluctuations in groundwater levels.
Comparing pre- and post-pumping static water levels.
Quick field checks during well installation or rehabilitation.

Frequently Asked Questions

Last updated: 2026-06-15 · Reviewed by Nham Vu