For your information these regulations are not new... the AG 51-2010 is extracted from the law of "aguas residuales" which dated from 2006. This particular Acuerdo Gubernativo just precise the minimum requirements in terms of residuals water from houses, businesses and mandate a 3 months time to get your system analyzed.
Do all business and private house owners have money to implement it... Well businesses and houses before anything should have already taken in consideration the law...and in Guatemala not knowing the law is not an excuse, specially for businesses or foreigners.
Does the government has the will to inforce it... well that's up to him... now the cianobacteria made it a necessity... as because to many people have not been respected the law...... "what will be controversial..."
I agree the AG 51-2010 is not very easy to deal with as it put everybody on the same level when a house, a small hotel or a big hotel should have different requirements... I personally think that the government should gives technicals guidelines in term of how to build a septic for the different sizes flow that will meet the requirements and then should proceed with random analyses.
Regarding the engineers to make the measures... well in Guatemala Ciudad a lot of laboratories have the know how to make these measurements but it is in the city and it makes it expensive for us around the lake to get them here... It is why for the ones interested, I'm working with an engineer and a laboratory from the city to get volume discount...