Raindrops keep falling on my roof!

By BOB ‘hot rod’ ROHR,

contributing writer

Being well versed in the piping trade, I’ve decided to try and wrangle some of those drops. Rainwater collection systems are getting a lot of attention again. I remember a lot of homes with cisterns in the basement as I grew up in the western New York area in the ‘60s. For the most part I remember those systems being used mostly for irrigation, specifically for lawn sprinkling.

These days I see more complete rain water systems being offered. The factory-built systems are available with various levels of filtration. The basic system might have a filter at the roof or down spout for leaves and debris. Some systems have clever valves, or collection tubes, which causes the first small batch of water to be dumped. This allows the roof to be rinsed, so to speak, washing the roof of any bird droppings, etc. before flowing into the tank. Good thinking!

Additional filters can be added at the inlet into the storage tank. Filtration can be installed as simple and basic as spin-on cartridges, or as high tech as a RO, UV and carbon filters. Chlorine can be added for disinfection and then the taste and odor can be removed via carbon block filter before going into the home. It is quite possible to turn rainwater into safe potable water, if desired. When you think about it, even sewage can be turned into potable water with enough technology.

My plan for my own home is to use the rainwater for toilet flushing and possibly laundry use. We have a great producing well for our domestic water in terms of gpm, but it is very hard and has high iron content. It takes a multi-stage, water-wasting filtration system to make it user friendly. With the rainwater component I hope to cut back on both water softener and rust filtration use.

The HDPE tank I purchased is not listed for potable water storage. I bought an underground style of tank with a 1,000-gallon capacity. The tank has two large manhole sized openings on the top. I piped some pvc lines into the tank for extracting the water and for wiring to add a level sensing system to cut the pump out as the level drops. I’m still trying to decide between a submersible and a variable speed well pump, mounted above the tank. I like the idea of the new variable speed, ecm well pumps that efficiently and without a large storage well tank.

Another option would be a PV powered pump. It would fit into my “green” theme. But I am considering the cost of a high gpm DC pump, with batteries. Is the juice worth the price? I like my green lean. I’m thinking about the Viega Manabloc system for my distribution with the rain water piping well labeled. I noticed a purple color pex is used in Europe to denote rain and gray water piping. Some green colored pex would be a nice match for rain or gray water systems. I did see some sample green pex manufactured from recycled pe. What a nice touch, to build a green pipe for green technologies.

Controls are another area I am still “noodling.” Certainly a seamless switch to well water should the rain water tank run low would be ideal, as the tank may run low and lock out when I am out of town, like the boiler does. Manual rainwater operation may not be what my wife wants on her list of to-dos.

My system is pretty much home-built with common off-the-shelf components. All of the parts and installation are well within the comfort level of readers here. My largest expenditure so far was the rental on a small mini-excavator for digging the hole for the tank and piping runs to the tank.

I also decided to build a small greenhouse over the top of the tank. I hope to heat this 60 square feet of slab-on-grade with solar and water the crops with collected rain water. I installed a pex loop below the under- slab insulation for a dump zone for the solar if needed. It would also act to pre-heat the earth below the well insulated slab. A pex loop is also included in the green house slab for cold weather tempering of the space.

The next step will be a separate HW tank, solar powered, of course, to heat the collected rainwater for laundry use.

I have noticed some factory-built systems showing up on the market. Texas seems to be a leading state when it comes to rainwater collection technology and components. Here is a link to a rainy day site should this technology grab your attention -- www.harvesth2o.com.

I recall rainwater being a crucial part of life in the islands, on a recent trip to St Croix. De-salination is slow and expensive; rainwater is a simple solution. But I am hearing rainwater collection may be banned in some areas. Certainly check into the codes and laws in your area should you decide to let some raindrops slide down the pipes to your system.                   

Bob “Hot Rod” Rohr has been knee-deep in plumbing, heating and solar work since he was a kid. He has learned a lot of simple ways to install, repair and update hydronic systems. Check out his new, downloadable “Cool Tips from Hot Rod” at www.showmeradiant.com.