AQTESOLV Alternatives for Pumping Test Analysis

HydroSOLVE has sold AQTESOLV since 1989. People look for an alternative for ordinary reasons: a computer that is not running Windows, a project that needs layered aquifers, a licence that sits on someone else's machine, or a need to script the analysis. This post compares the alternatives we know of, with what each is suited to. One of them, PumpPilot, is ours, and we say where it falls short.

What does AQTESOLV do that an alternative has to match?

AQTESOLV analyses pumping tests, slug tests and constant-head tests in confined, leaky, unconfined and fractured aquifers. HydroSOLVE lists variable-rate, single-well, recovery and step-drawdown tests, bounded aquifers, overdamped and underdamped slug tests, derivative analysis, and both visual and automatic (nonlinear least-squares) curve matching. It runs on Windows 8, 10 and 11 and is sold as a commercial licence in Standard and Pro versions, with a demo to download.

Few alternatives cover all of that. Before choosing one, decide which tests you actually run. If you need slug tests, the list gets shorter.

What is the best alternative to AQTESOLV?

For a commercial program with the same breadth, including slug tests, the closest match is AquiferTest from Waterloo Hydrogeologic. For layered aquifer systems, MLU is the specialist. For free pumping test analysis in a browser, PumpPilot covers the standard solutions. For scripted or reproducible work, the Python packages welltestpy and timflow are open source.

Tool	Developer	Licence	Runs on	Slug tests
AQTESOLV	HydroSOLVE, Inc.	Commercial (Standard, Pro)	Windows	Yes
AquiferTest	Waterloo Hydrogeologic	Commercial (Standard, Pro), trial available	Windows	Yes
MLU	CEMS BV, first written by Dr C.J. (Kick) Hemker	Commercial, free trial	Web browser	Yes
USGS spreadsheets (OFR 02-197)	U.S. Geological Survey	Free download	Microsoft Excel	Yes
welltestpy	GeoStat-Framework	Open source (MIT)	Python	No
timflow (formerly TTim)	Mark Bakker, Davíd Brakenhoff	Open source (MIT)	Python	Yes, in its examples
PumpPilot (ours)	GeoPilot AI	Free, with a Pro plan	Web browser	No

Is AquiferTest a good replacement for AQTESOLV?

Yes, if you want a commercial desktop program that covers the same kinds of test. AquiferTest analyses pumping tests, slug tests and Lugeon (packer) tests, in confined, unconfined, leaky and fractured aquifers. Waterloo Hydrogeologic lists fully and partially penetrating wells, multiple pumping wells, variable rates, barrier and recharge boundaries, and the Moench and Warren-Root fracture-flow solutions. The Pro edition adds diagnostic and derivative plots, barometric compensation, trend correction and automatic type-curve matching. Version 15.0 came out in January 2026 and added reporting of Bouwer-Rice and Dagan slug test parameters. It reads logger files directly, including Level Logger (.LEV) and Diver (.MON) files.

If your firm already standardises on Waterloo Hydrogeologic products, or you run Lugeon tests, it is the natural choice.

When is MLU the better choice?

MLU suits tests in layered systems, where the Theis or Hantush-Jacob picture of one aquifer is too simple. It models aquifer layers with horizontal flow separated by aquitards with vertical flow, and fits the parameters with the Levenberg-Marquardt method. CEMS lists recovery tests, variable-discharge tests, step-drawdown tests, tests in well fields and slug tests, all in one interface. Pumping wells can have wellbore storage and skin.

Kick Hemker wrote MLU, and CEMS took it over when he retired in 2020. MLU now has a fully web-based interface reached through the CEMS NUCLEI portal. CEMS says projects are imported and exported as project files and no data is stored on external servers. It is commercial software with a free trial.

Is there a free AQTESOLV alternative?

Yes. There are several, and for a standard constant-rate test with observation wells they are often enough.

The USGS aquifer-test spreadsheets

Keith Halford and Eve Kuniansky's Open-File Report 02-197 is a set of free Excel spreadsheets for pumping and slug tests: Cooper-Jacob (with recovery and well efficiency versions), Hantush-Jacob leaky aquifer, distance-drawdown, step-drawdown, the Jacob-Lohman method for flowing wells, and the Bouwer-Rice, Cooper-Bredehoeft-Papadopulos and van der Kamp slug test methods. The current version, 1.2, dates from 2004, so they work but have not been updated since. The report itself warns against estimating storage from single-well tests, which covers most of the sheets.

PumpPilot

PumpPilot is our tool. It analyses pumping tests in a web browser, and the readings stay on your computer because the calculations run in the browser tab. It fits the Theis, Hantush-Jacob, Papadopulos-Cooper and Neuman solutions to any number of wells at once, and has the Cooper-Jacob, Theis recovery and step-drawdown methods. It plots the drawdown derivative, can rank solutions by AICc, and lists cautions about the fit, such as residuals that are correlated in time. The analysis is free; a Pro plan raises the limits on cloud projects and the assistant.

What it does not have yet: slug tests, partially penetrating wells, hydraulic boundaries, storage in the aquitard, and fractured or double-porosity aquifers. If your test needs any of these, use one of the other tools.

welltestpy and timflow (TTim)

If you work in Python, two open-source packages are worth knowing. welltestpy, from the GeoStat-Framework group, handles pumping test campaigns: it estimates parameters with the Theis and Thiem solutions and with extended versions of them for heterogeneous aquifers, and includes diagnostic plots and a Cooper-Jacob correction. Its API has no slug test classes.

TTim, Mark Bakker's transient multi-layer analytic element code, has moved to timflow, maintained by Bakker and Davíd Brakenhoff; the TTim repository says it will no longer be developed. timflow's documentation works through confined and leaky pumping tests (Oude Korendijk, Gridley, Sioux Flats, Dalem, Texas Hill among them), unconfined tests and slug tests, calibrating the model to the readings. It is the most flexible option here and needs the most setup.

Which AQTESOLV alternatives handle slug tests?

AquiferTest, MLU, the USGS spreadsheets and timflow all handle slug tests. PumpPilot and welltestpy do not. For a quick Bouwer-Rice analysis with nothing beyond Excel, the USGS spreadsheet is the shortest route. For underdamped (oscillating) responses, check the method list of each tool before relying on it: AQTESOLV lists underdamped slug tests explicitly, and we did not confirm the same for every alternative.

How do you check that an alternative agrees with AQTESOLV?

Run a test with a published answer before trusting a new tool on your own data. The AQTESOLV manual's Gridley, Sioux Flats and Texas Hill tests suit this: timflow's documentation analyses all three, and PumpPilot opens on Sioux Flats. On that test PumpPilot's Theis fit gives a transmissivity of about 4310 m²/d, against the 4308 m²/d reported for AQTESOLV. PumpPilot's calculations come from pumptest, an open-source (MIT) library, and its validation page sets its results beside AQTESOLV and welltestpy on these published tests.

Agreement on a textbook test shows that the solution is coded correctly. It does not show that the solution suits your site; the derivative plot and what you know of the geology decide that. If you are choosing numerical models rather than test analysis tools, our sister site has a comparison of groundwater modelling software.

Try PumpPilot

PumpPilot opens in the browser with nothing to install, and you can fit your first test on the Sioux Flats example before entering your own readings. The documentation covers entering a test, choosing a solution, reading the fit and its cautions, and the reference page lists what is not in PumpPilot yet.