Memphis aquifer protection and groundwater monitoring

At a glance

Based on auto-generated captions; names and details may be misheard.

What: how to protect the Memphis aquifer (the source of the city's drinking water) from data center water use and from contamination, raised at the second Planning & Zoning data center hearing on 10/19/2026.
Where it stands: information gathering only; no vote. Experts described monitoring options (extra sampling, sentinel wells, private-well sampling) and the county well permit process. Council members asked what the city can require.
Next: Spinosa said he hopes to bring TVA back at a later hearing; a temperature study of the aquifer would take about six months for first data. See Data center legislation hearing series.

Waldron (University of Memphis, CAESAR) said quantity is not the problem: about 57 trillion gallons lie in the Memphis aquifer and MLGW's pumping has fallen about 30 percent over two decades. Quality is the concern, and the aquifer water is thousands of years old and naturally filtered.
Contamination can come from natural leakage from the shallow aquifer as the deep one is drawn down, or from spills, with slow chronic leaks the worry. In a wet season a surface contaminant reached the water table in about three weeks; once in the Memphis aquifer it moves very slowly sideways.
His team mapped about 14,000 potential legacy contamination sources countywide. Waldron suggested extra monitoring (not just routine), such as sampling groundwater before and during an operation to build a baseline, and said sentinel wells were set up for the Blue Oval megasite. He recommended similar extra monitoring on the earlier pipeline project.
Waldron said there are roughly 600 to 700 private wells that could serve as early-warning sentinel wells if the county health department shares its records; that sampling would be through county funding, not the city.
Researchers have found 13 or more new suspected breaches in the protective clay layer in two years. Two are known in the Ensley Bottoms area, one near TVA. A health department speaker stressed that breaches are naturally occurring.

Anyone drilling a well in Shelby County needs a health department permit. Alexander said applicants with access to MLGW water are automatically denied and may appeal to the Shelby County groundwater quality control board; the department also weighs flood zones, sewer tanks and gas stations. Madden noted that Bartlett, Millington, Arlington and Collierville run their own water systems.
Outside the MLGW area along the Mississippi River, Waldron said a company would mainly need a well permit. The health department says it tests eight TVA wells near the xAI site for coliform, dissolved solids, pH and nitrates.
Warren urged the experts to carry upstream a request for monitoring data from wells near existing data centers; Waldron said he could not commit.

Asked by Logan about closed-loop cooling, Waldron said returning heated water to the aquifer would need a study first; water would have to be cooled before it goes back. No similar study is known elsewhere. His team is placing temperature sensors in monitoring wells, with first data in six or more months. Warren said ordinances may need a temperature limit and a stop point.

About 38 minutes across 1 meeting (from transcript timestamps; approximate).

Meeting	Minutes
2026-10-19 - Planning & Zoning	38

2026-10-19 - Planning & Zoning — Waldron, MLGW and Shelby County Health Department staff briefed the committee on aquifer quantity and quality, monitoring, well permits and heat from closed-loop cooling.