What it is
STANAG 2136 is a NATO Standardization Agreement, currently Edition 7, dated 19 October 2022. It is not a technical specification. It is the agreement by which NATO nations commit to implement AMedP-4.9, Edition B, the Allied Medical Publication covering requirements for water quality during operations. The document's own aim is "to respond to the following interoperability requirements": under those requirements, participating nations agree to follow the risk management procedures described in AMedP-4.9, and agree to notify other armed forces participating in mutual logistical water support when they are unable to meet AMedP-4.9's requirements. Read on its own, STANAG 2136 requires nothing of a supplier or contractor. Its obligations run to nations and to NATO's own bodies, and the substantive water quality requirements sit in AMedP-4.9, not in this cover.
Who it binds, and how
STANAG 2136's letter of promulgation describes the enclosed agreement as one "which has been ratified by member nations, as reflected in the NATO Standardization Document Database (NSDD), is promulgated herewith." Under "Agreement," participating nations agree to implement AMedP-4.9, Edition B - a national commitment, made by ratification, not a duty a supplier signs up to by reading this document. Nations that have not already done so are invited to "advise the NSO of their intention regarding its ratification and implementation." So "is STANAG 2136 mandatory" has no single answer: it depends on whether a given nation has ratified and implemented it, and this cover names no supplier, manufacturer or contractor at all.
What implementation actually looks like
STANAG 2136 is implemented "when a nation has issued the necessary orders or instructions to authorities and units concerned putting the requirements detailed in this agreement into effect." AMedP-4.9 itself is considered implemented once a nation has updated its procedures for the quality of water provided to troops during operations and its field water testing capabilities. To get there, the document says nations must establish a standardised approach for ensuring water quality, install a water safety plan, agree in aim to provide potable water that is "free of microbiological contaminants and substances in concentration that can result in adverse health effects," set minimum requirements and maximum levels for water constituents, and establish minimum field testing capability. Day-to-day, water harvesting, preparation and disinfection can be treated as a logistics function or contracted out, testing can be carried out by field laboratories or contracted as well, and assessing test results and deciding on countermeasures is described as mainly a duty of force health protection and medical personnel.
A cover agreement, not the water quality requirements themselves
A reader who only has STANAG 2136 in hand does not yet have the substance it points to. That sits in AMedP-4.9, Edition B. The cover also names four further related documents in sequence: STANAG 2556, food safety, defence and production in support of NATO operations; AMedP-4.5; STANAG 2535, deployment health surveillance; and AMedP-4.1. Edition 7, dated 19 October 2022, supersedes STANAG 2136, Edition 6, dated 21 March 2014.
Reporting and review
Allies and NATO bodies must report implementation details through the electronic reporting tool, and partner nations are invited to do the same. Once implemented, nations are expected to keep working to improve the STANAG and send proposals to the custodian. The STANAG itself must be reviewed in accordance with AAP-03, with the result recorded in the NSDD, and the agreement is supervised under NATO's medical standardization committee chain (COMEDS, MCMedSB, MedStd, FHP, FWSVS P). STANAG 2136 names no assessment or certification scheme of its own: the only stated check is that periodic review, not an audit of anyone's water testing.