Tuesday, May 8, 2012

Why free water isn't cheap.

For many years I've been growing orchids and other plants as a hobby. Over the years I've killed many plants for various reasons but one of the worst reasons is that city water is bad for some plants. Now some plants really don't care and do quite well but the minerals and chemicals in city water can be very harsh for delicate plants like orchids and eventually can kill them. In some cases you will quickly kill some species by just watering them a few times with city water. A lot of people will use distilled water or reverse osmosis water systems just so they can grow those types.

Another thing about city water is that it's expensive and not getting cheaper. Also in San Diego where I live, the more water you use for any reason increases your sewer bill. So as a single person with a garden, I'm paying sewer rates as high as a family with no garden. So for many years I've thought about collecting rainwater to water my plants. Rainwater is naturally clean and free from harmful chemicals and minerals. San Diego is basically a coastal desert that has been turned green with irrigation. We get a good amount of rain but almost all of it comes during winter and then it can be dry for many months. We can go all summer without a rain storm of any consequence. This means that collecting rainwater is not a very common thing here. You kind of think about it when it's raining but then you think it won't rain for a long time so is it really going to work?

So you think you would just stick some barrels out in the yard and point the downspout at them. Well it can be that simple but and that is fine for pouring water on trees or lawns but not what I needed to water my orchids. I did a lot or research online into what people were doing for rain collection and also looked at various commercial products available. As it turns out, it's not cheap to collect free water. I decided I was going to try and do as much of the design myself.

The first flush is very important.

One of the first things you learn about rain harvesting is that the surface you're collecting the rain from is very important. In my case, I'm collecting the rain from the roof of a room addition on the back of my house. This roof is only about 240 square feet. As you can imagine a roof gets dirty between rain storms. So when it first starts raining, you don't want to collect that water as it will have dirt and contaminants that can undo what you're trying to accomplish. Because of this, you need to install some sort of diverter to let the first amount of water bypass your rain barrels.

There are multiple ways to do this. The simplest system is a manual bypass in your downspout that just diverts the dirty water past your barrels. Once it has rained for a while, you switch it over so the water goes into the barrels. Beyond that, there are many systems that have been devised to automatically perform this task. I was originally going to use a design that has a pipe that the first water goes into and there is a ball that floats up and then causes the water to be diverted to the barrels. After adding up how much it was going to cost to put this together, I decided to use a commercial diverter made in Australia called the Clean Rain Ultra. This system works pretty well.

The next important part is the barrels. Again there are a lot of choices. I decided I wanted to use recycled barrels since they are readily available and reasonably priced. After doing a lot of research, I settled on some 50 gallon terra cotta colored plastic food grade barrels. I found San Diego Drums & Totes through a craigslist ad. They have various types of barrels. You have to stay away from white barrels to avoid algae problems. Originally I bought two barrels to get my system going and then decided to expand to six. Or course when I went back to get more, the ones they had were different from the first ones. So in the end, I bought six new ones so that they would all match and work together. The first two will be added on later.

As you can see in the pictures, I've lined up the barrels behind my lath house so that they'll be close to the plants. I ran piping below ground to get the water from the house to the barrels. I also connected the downspout into the yard drain so that the first flush water goes there instead of onto the ground. I had to install a new gutter on the house as well and added screens on top to keep large debris out. I first started my system in January and finished it in the middle of March. Since the middle of January, I've only watered my Orchids and other potted plants with rain water. So far I haven't killed anything and the plants are doing well. So far I'm very happy with how it's going. I may expand the system to collect rain from the main house roof so that I can do all my landscape watering without city water. Below is a video showing how the system works and additional pictures.

A note about rebates.

As I was working on my system, I found out that the City of San Diego has a Rain Harvesting Rebate Program. I thought great, this will help me offset the cost of my system. Well it turns out there is a slight hitch. Homemade rain barrels are not eligible. That's not to say that you can't use recycled barrels, they just have to be sold by business that has converted them into rain barrels. Basically if you pay someone else to drill a hole in the bottom, they qualify. I appealed to the city and they didn't seem to care. But if you want to buy commercial rain barrels in San Diego, please do take advantage of the rebate. At least it will help someone. For me, the rebate doesn't bring down the cost of barrels cheaper than what I paid.

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