Our healthcare project is planning on capturing condensate water and excess rain water from a 12,000 s.f. vegetated roof in a cistern to irrigate plantings which include a small lawn area in a courtyard. We will have a combination of drip irrigation and regular spray irrigation. We anticipate most of the water will come from the condensate (the storm draini for the vegetated roof is very convenient to the cistern). We will have plenty of condensate to water the plants when they would need it. We are selecting native and drought resistant plantings except for the lawn grasses. The irrigation subcontractor has raised the question of potable water use. He believes that the reclaimed water must be treated so that it is potable. His argument is that the landscapers will drink from this water in spite of any signage in any language. I believe that we can educate our way out of this concern.
However, my larger concern is over the health impacts of patients coming into contact with the water. I think that we can shut down the concerned courtyard during watering and give it some drying time. I am not finding any good resources on health impacts in this case. Has anyone else used condensate successfully to water plants? Were there or are there health concerns? At this time, I would like to not add surface stormwater to the mix because of debris. We would filter the water but originally planned for basic filtration.
Emily Catacchio
Sustainability SpecialistWight and Company
610 thumbs up
February 8, 2012 - 6:37 pm
Susan,As I understand it, it is good practice (though I'm not certain it's required) to treat grey water used in traditional spray irrigation applications to potable standards. The reason being, that you are essentially airating the water, thus making any pathogens or contaminants airborne and potentially causing a health concern.This is not a concern with drip irrigation, thus (I gather) it is not generally treated to potable standards.As far as the concern that people will drink out of your grey water system, that has the potential for some serious health issues. All associated pipes and spouts need to be clearly labeled and restricted (I suppose) if it is a major concern that the signs would be ignored.
Susann Geithner
PrincipalEmerald Built Environments
1297 thumbs up
February 13, 2012 - 1:40 pm
Actually most companies providing gray water reuse systems specifically call out that their system can only be used in combination with drip irrigation. Sprinkler are not allowed for non-potable water because of the health concerns. I'm don't know which code includes that requirement or if this is more so because of the potential for a law suit, but the manufacturer certainly call it out specifically.
Susan Walter
HDRLEEDuser Expert
1299 thumbs up
February 13, 2012 - 2:18 pm
Thanks to both of you! I met with the irrigation consultant who was much more positive and had better solutions than the landscaper initially did. He took the sprinklers out for the same concerns but added in something he called a bubbler at a few tree locations. We can also lock out the courtyard and water early in the morning so the plants have time to dry out.
I asked the irrigation guy directly about workers drinking the non potable water. I was armed with research that shows this is not a new idea (they have been doing this in LA since the 30;s). He was not concerned and as an landscaper employer he simply tells the workers that they can't drink from the hose explaining why. Turns out this is becoming standard practice and the workers are becoming accustomed to not do this.