WEF Discussions — Now on LinkedIn!

WEF is pleased to announce the creation of free LinkedIn groups associated with its technical discussion forum topics. Through these LinkedIn groups, members will be able to view and participate in discussions, as well as communicate with one another via direct messages. Share your experiences and knowledge, ask questions and respond to other discussions as frequently as you like!

You must have a LinkedIn profile to join a LinkedIn group; you can create your profile here. If you already have a LinkedIn profile, all you need to do is submit a request to join one or all of the following groups:

Water Environment Federation (Main) | Biosolids | Collection Systems | Nutrients | Stormwater 
Utility Management | Water Reuse | Water for Jobs | Watershed Management | Laboratory Practices 

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Posted: Wednesday, February 20, 2013 8:17 AM
Joined: 2/20/2013
Posts: 2

I would like to understand the correct way to use ND and <? Thanks

Posted: Thursday, February 21, 2013 7:42 AM
Joined: 10/5/2009
Posts: 49

The use depends on the information required by either clients or the regulating authority.  However, it is poor lab practices to use ND if you don't have your reporting limits listed somewhere on your report.  It's generally easier for report recipients to use <RL, where RL is your numerical reporting limit for that analyte.


Note that for NPDES work, it's now common practice to list both your MDLs and MRLs (or LOD/LOQ, however you want to call them) with results between the two flagged as estimated.


Chuck Lytle, City of Portland (OR)

Posted: Monday, February 25, 2013 10:22 AM
Joined: 4/8/2010
Posts: 9

If you're asking in terms of what to report on your discharge monitoring report, I'd reiterate to first read through your permit, and if nothing is there, check with either your lab certification agency &/or permit writer.  Some states have a specific format they want you to use when completing your DMR's.