Puna Water Harvesting Thread (fit in, real estate, insurance)

[Misterperfect]

Hey CDF,

I'm thinking about buying a lot or two in Puna on the Big Island (BI) and am curious about water harvesting practices on BI in general.

- Ive looked at a lot of previous posts but thought it might be nice to have info just about water harvesting in one thread.

- Im posting this in the Hawaii Big Island section which is usually reserved for questions about moving to Hawaii for the 'Real Estate moguls' but thought this question might also be appropriately posted here.

- Ive looked at several different online resources but i thought id also ask the CDF group to chime in if they have any real world experience harvesting, treating and using rain water on BI.

- If you dont harvest water thats ok too just add something constructive. CONSTRUCTIVE

- I understand it may have been years since you installed your systems but thats OK, no worries.

These are some of the questions ive run into so far:

1) What kind of water catchment tank do you use. Plastic, concrete, glassfibre, etc.

2) How many gallons does your tank hold?

3) Where did you buy your tank?

4) Whats your water treatment method? Filter, UV

5) Who built your tank?

6) How often do you clean your tank?

7) Do you ever get sick from water born illnesses?

8) Whats the worst thing you ever found dead in your tank?

9) Metal roof collectors or other?

10) Best Rain Gutter material?

If you are bored by constantly having to answer noob questions like this, please, just refrain from posting if you can. lolz
If you have a hilarious story about this topic of water harvesting please tell it.

Thanks CDF,

Mr. P

[hotzcatz]

https://www.ctahr.hawaii.edu/oc/freepubs/pdf/rm-12.pdf

and

https://www.ctahr.hawaii.edu/hawaiir...ontaminate.pdf

Two .PDFs you can down load about water catchment systems in Hawaii. The U of H has a whole lot of recommendations on them.

And, here's the link to the website if you don't want to download .PDFs:
https://www.ctahr.hawaii.edu/hawaiirain/

Generally, most people use above ground 'doughboy' swimming pools as their catchment tanks. They generally have a cover on them to keep things out. They generally have metal roofs. And they generally use plastic rain gutters and PVC / CPVC piping for the rest of the system. I'd say about 90% of the house plans I've drawn up which had catchment systems on them used these parameters.

If you want to get fancy on the catchment side, some folks have a diverter system which doesn't catch the first bit of rainfall but lets that fall outside the system. The reasoning behind that is that it washes a lot of debris from the roof and keeps it out of the system.

Filter systems run the gamut from none at all but they bring in their drinking water, to all sorts of fancy UV and reverse osmosis filter systems. Some folks put chlorox or clorine in their tanks, some don't.

You'll also need a pump for the water and most folks have a pressure tank as part of the pump system to keep the pump from having to cycle so often.

[Misterperfect]

Originally Posted by hotzcatz

https://www.ctahr.hawaii.edu/oc/freepubs/pdf/rm-12.pdf

and

https://www.ctahr.hawaii.edu/hawaiir...ontaminate.pdf

Two .PDFs you can down load about water catchment systems in Hawaii. The U of H has a whole lot of recommendations on them.

And, here's the link to the website if you don't want to download .PDFs:
https://www.ctahr.hawaii.edu/hawaiirain/

Generally, most people use above ground 'doughboy' swimming pools as their catchment tanks. They generally have a cover on them to keep things out. They generally have metal roofs. And they generally use plastic rain gutters and PVC / CPVC piping for the rest of the system. I'd say about 90% of the house plans I've drawn up which had catchment systems on them used these parameters.

If you want to get fancy on the catchment side, some folks have a diverter system which doesn't catch the first bit of rainfall but lets that fall outside the system. The reasoning behind that is that it washes a lot of debris from the roof and keeps it out of the system.

Filter systems run the gamut from none at all but they bring in their drinking water, to all sorts of fancy UV and reverse osmosis filter systems. Some folks put chlorox or clorine in their tanks, some don't.

You'll also need a pump for the water and most folks have a pressure tank as part of the pump system to keep the pump from having to cycle so often.

Thank you Catz.
I appreciate your expertise.

Mr. P

[terracore]

"Generally, most people use above ground 'doughboy' swimming pools as their catchment tanks. They generally have a cover on them to keep things out. They generally have metal roofs."

In Puna, most catchment tanks are 10,000 gallon galvanized steel tanks with a FDA-approved white plastic liner. 10,000 gallons seems to be the minimum size required by mortgage or insurance companies. Metal catchment roofs are very uncommon (a metal roof costs as much as the tank does, and putting a roof on the tank requires the tank to be reinforced, which makes the tank more expensive). Most catchment tanks have a top steel frame (they use 1" galvanized electrical conduit pipes) that is covered in shade cloth. Depending on the cloth and tropical storms, the cloth gets replaced every 5-10 years. The plastic tank liner gets replaced every 15-20 years. The tank should last as long as your house roof if you take care of it.

If you are looking for estimates, I recommend Island Catchment in HPP. Last I looked a 10,000 gallon steel catchment tank with liner, conduit frame, and shade cloth was about $5k. A tank with a metal roof is about 15k. Don't go with somebody you've never heard of. A friend of mine had his catchment tank burst because it wasn't put together correctly. The same outfit installed his neighbor's tank and when his burst, it went towards the house and the water knocked the house off the post-and-pier construction. This was down by South Point.

The pump and filtration system generally isn't any different than what common well systems use and are "off the shelf" components. Because of that, the pumps are frequently way over powered (you are moving water horizontally, not vertically). We added a UV sterilization system to our water system because it's a whole-house solution. Reverse osmosis is generally only used at one sink.

A typical scenario is:

Roof--> Tank--> Pump--> Pressure tank--> 20 micron filter--> 5 micron filter--> UV unit--> Home plumbing system

Measured with a TDS unit the water from our tap is cleaner than municipal and bottled water.

[Misterperfect]

Originally Posted by terracore

"Generally, most people use above ground 'doughboy' swimming pools as their catchment tanks. They generally have a cover on them to keep things out. They generally have metal roofs."

In Puna, most catchment tanks are 10,000 gallon galvanized steel tanks with a FDA-approved white plastic liner. 10,000 gallons seems to be the minimum size required by mortgage or insurance companies. Metal catchment roofs are very uncommon (a metal roof costs as much as the tank does, and putting a roof on the tank requires the tank to be reinforced, which makes the tank more expensive). Most catchment tanks have a top steel frame (they use 1" galvanized electrical conduit pipes) that is covered in shade cloth. Depending on the cloth and tropical storms, the cloth gets replaced every 5-10 years. The plastic tank liner gets replaced every 15-20 years. The tank should last as long as your house roof if you take care of it.

If you are looking for estimates, I recommend Island Catchment in HPP. Last I looked a 10,000 gallon steel catchment tank with liner, conduit frame, and shade cloth was about $5k. A tank with a metal roof is about 15k. Don't go with somebody you've never heard of. A friend of mine had his catchment tank burst because it wasn't put together correctly. The same outfit installed his neighbor's tank and when his burst, it went towards the house and the water knocked the house off the post-and-pier construction. This was down by South Point.

The pump and filtration system generally isn't any different than what common well systems use and are "off the shelf" components. Because of that, the pumps are frequently way over powered (you are moving water horizontally, not vertically). We added a UV sterilization system to our water system because it's a whole-house solution. Reverse osmosis is generally only used at one sink.

A typical scenario is:

Roof--> Tank--> Pump--> Pressure tank--> 20 micron filter--> 5 micron filter--> UV unit--> Home plumbing system

Measured with a TDS unit the water from our tap is cleaner than municipal and bottled water.

Very helpful and informative.
Thanks

[tpirsig]

I'm curious about folks that don't put bleach in the tank. How do you keep the water in the tank from turning quite green?

Like mine does if I forget about it for awhile :0

[leilaniguy]

Have you tried pool salt and a few pennies? Supposed to work. You still have to skim off the dead rats and coqui. Did that for 14 years. Now I'm on piped water, much better!

[hotzcatz]

The metal roof is generally on the house, not the catchment tank, I guess the way it was written earlier it could have been construed to have been a roof over the tank. But, metal roofing on the house as opposed to composite shingles or any other type of roofing.

[david1952]

any effects

[tpirsig]

Never even heard of doing this -- am quite curious. Looking on the internet I see it's popular for swimming pools -- but is it commonly done for catchment systems?

Originally Posted by leilaniguy

Have you tried pool salt and a few pennies? Supposed to work. You still have to skim off the dead rats and coqui. Did that for 14 years. Now I'm on piped water, much better!