How Deep Does a Water Well Need to Be in Mobile County, AL? A Water Well Drilling Guide

If you own property in Mobile County, AL, and are considering a private water supply, water well drilling depth is one of the first questions to understand. The answer is not a single number. Depth depends on local geology, the aquifer you are targeting, your intended use, and your distance from Mobile Bay and the Gulf Coast. Here is what drives those decisions.

What Makes Mobile County's Geology Different for Well Drilling?

Mobile County falls within the East Gulf Coastal Plain, one of Alabama's five hydrogeologic provinces. Unlike areas underlain by hard rock, the coastal plain is built from layered sediments, and that directly affects how deep a well needs to go.

A sand and gravel aquifer underlies roughly 6,500 square miles of southwestern Alabama, supplying most of the groundwater used by rural communities across Mobile, Baldwin, Washington, and Escambia counties. Because this formation is layered, water-bearing zones appear at varying depths from one property to the next. A well on the north end of the county may hit productive sand at a very different depth than one closer to Mobile Bay.

How Deep Do Most Wells Go in Mobile County?

Water table depths in the Coastal Plain typically range from 30 to 150 feet, and the average residential well depth in Alabama is around 180 feet. A licensed local driller can narrow that range using nearby well logs and geological surveys for your specific parcel.

Several factors push or pull that number in Mobile County.

Location within the county. Properties near Citronelle or Satsuma in northern Mobile County may access shallower sand and gravel formations than those closer to the bay. Areas near the Tombigbee River delta and Mobile Bay tend to have more complex layering.

Saltwater intrusion near the coast. Saltwater occurs at relatively shallow depths near the Gulf Coast, and freshwater aquifers can become contaminated if wells are pumped heavily enough to draw it in.

Intended use. A household well and an irrigation well may target different aquifer zones. Agricultural projects often require higher yield and may need to penetrate deeper into the formation.

Clay layers and confining beds. Clay beds and lenses are common throughout the aquifer. Where clay beds are thin or absent, water is under unconfined conditions. Where they are thick, artesian conditions can develop. An experienced driller reading local well logs can identify the most productive zones for your parcel.

Permitting and Regulatory Basics for Mobile County

Water well drilling in Alabama is regulated by ADEM. As a homeowner, you do not file permits yourself. The licensed driller files ADEM Form 060 (Notification of Intent to Drill) before work begins and a Completion Report within 30 days after finishing.

For higher-volume wells, an additional layer applies. Any well pumping 50 gallons per minute or more, with a surface location in the coastal area or a 50-year capture zone extending into it, requires a separate ADEM coastal area permit. Most residential water well drilling projects fall well below that threshold, but agricultural, commercial, and industrial projects should confirm this early.

ADEM recommends a minimum setback of 100 feet from septic systems and 150 feet from cesspools, lagoons, barns, and chemical storage areas. Check with the Mobile County Health Department for any additional local requirements before drilling.

Key Factors That Affect Required Well Depth

A licensed driller will evaluate the following before recommending a target depth for your Mobile County water well drilling project: distance from Mobile Bay due to saltwater intrusion risk, whether the site is in a rural or urban part of the county, sand and gravel formation depth estimated from nearby well records, intended use and daily flow rate requirements, and local clay layer thickness affecting artesian conditions or access to lower water-bearing zones.