Location Unique Identifiers (LUIs)

What is a LUI?

A Location Unique Identifier, or LUI, connects a sample location to a distinct spot on the Minnesota map. Each LUI has its own GIS coordinates, and no two LUIs occupy the same location.

Experienced EQuIS users will recognize that a “LUI” is another term for sys_loc_code in the EQuIS database.

When do I need a LUI?

The MPCA assigns LUIs to new sample locations, and all sample locations need LUIs.

Some sample locations may already have assigned LUIs. For example:

  • Previously-sampled sub-slab ports, rooms in houses and outdoor air samples may have existing LUIs. 
  • In rare cases, borehole locations may have existing LUIs. Borehole locations are considered unique even if they are located within feet of a previously-drilled borehole; however, the MPCA may consider an exception to this rule for boreholes drilled specifically for confirming historic analytical results. Discuss this with the MPCA Project Manager prior to reusing the LUI.
Please do not generate new LUIs for locations that already have LUIs assigned. 

If you are uncertain if a location you plan to sample already has an assigned LUI, ask the MPCA Site Project Manager or email Remediation EQuIS at remequis.mpca@state.mn.us.

Note: The MPCA does not issue LUIs for permanent wells. Permanent well LUIs are Minnesota County Well Index Unique Well Numbers as LUIs, which are located on the well permit issued by the Minn. Department of Health.

Do I need LUIs for each sample collected from a borehole?

No. LUIs are specific to a location, not a sample type. You can collect multiple soil samples, soil gas samples and groundwater samples from a single borehole, which is assigned just one LUI.

How do I get a LUI?

The figure below shows the most common LUIs and how to obtain them.

Before you generate LUIs, make sure they do not already exist for the locations you plan to sample.

How to obtain a LUI

Location Type Example LUI How to get the LUI
Permanent Wells 651347 Use the MN Unique Well number assigned by MDH

Well — Temporary
Well — Soil Vapor Monitoring
Borehole (soil sampling, test trench and sump)

Use Self-Service LUI Generator
Gas — Subslab
Building — Interior (indoor air)
Building — Exterior (outdoor air)
Land (Surface Soil Sample)
Sediment (lake/stream)
Surface Water
Assigned by MPCA — send request to:

How do I use the LUI Generator?

The LUI Generator application requires you to enter your name, an email address, a location type and the number of LUIs needed for each location type. To obtain LUIs for multiple location types, re-run the generator for each location type.

Do I enter a Site ID?

No, we associate LUIs with EQuIS sites when EDGE EDDS are uploaded to our EQuIS database.

Can I generate extra LUIs?

Yes, you can generate extra LUIs if you think you may need them, or if you want to have an extra for unexpected field conditions. There is no need to save unused LUIs for subsequent sample events.