My experience with drip irrigation like you are talking about is remote--I toured a setup in Arizona a number of years ago, and my next door neighbor converted his irrigation system to drip a couple years ago, which he kindly let me help with on occasion. So, take my comments as being from more of an observer. The drip systems are pretty much entirely plastic. There may be some metal, but it isn't common. These systems are rated for a useful life of 15-20 years, so the corrosion resistance of the plastic would give it an advantage over metal. I have been doing some surface drip on some trees for probably 7 years now with a used drip system. Each zone is controlled with a plastic ball valve and I have had no problems with these valves. The T tape that I have seen is buried from 8 to 16 inches deep as you don't want to water the surface of the soil except for germination. After that, you want to keep the surface dry to help control weed germination. In addition, the tape is buried deep enough that it won't be damaged by plowing or other field operations, and being deeper helps to hide it from moles and gophers which love to chew on the tape. If you do put it shallower, you could probably pick it up in the fall and store it inside when used on a small area such as a garden. I wouldn't think it would move in the soil, although if the lines get moved or kinked, when they get pressurized they will straighten out. I have also seen drip lines laid out on vegetable crops on bedded rows and covered with black plastic. Don't know if this was T tape, though. However, with the surface use, it appeared the plastic was removed and the tubes rolled up after the crop was off. Don't think there was anything used to hold the tubes in place, though. When it comes to the fall, my neighbor blows out the main lines and the drain line at the other end. He doesn't try to blow out the T tape itself as it has the emitters so has very little to no water in it when not running, and if ice does form it can expand inside the tubing without problem since the tubing is pretty well empty. Whether or not you use a quick connect for blowing the lines out depends on how much time you want to spend blowing the lines out in the fall. Since my neighbor is using settled and filtered ditch water, at the end of each daily water cycle on each zone, he opens the drain valve on the drain line and blows water out for a minute or two to help clear any sediment and protect the life of his investment. I have heard many times that the lines should receive some treatment periodically to prevent minerals from depositing in the emitters, and to control any bacteria that may be growing in the tubes to prevent them from forming gooey deposits that will accumulate sediment and plug the emitters. Usually, this is done by injecting sulphuric acid or phosphoric acid into the irrigation water one or more times during the year to achieve the desired pH of the water to remove the mineral deposits. The frequency of this will depend on the mineral content of the water, though. They also use phosphoric acid, which is a weaker acid, but also provides phosphate fertilizer to the plants. Sulphuric acid will also fertilize the soil with sulphur, if it is needed. If you don't treat the lines occasionally, you are likely to end up with deposits that will gradually plug the emitters and shorten the useful life of the tape. In a garden situation where the cost of what you are using is relatively small compared to a field situation, shortening the life of the tubes by a few years may not be a concern, but it will depend on the mineral content and other contaminants in your water. Good luck!

AM, Yes most controllers are not as flexible as you would like. The more money the more flexibility. I am not even aware of a 6 program controller. Someone may know. What was the old one that you used? I just need to gather more information from you to make an informed suggestion. I need to know your flow rate of your water source. Is your system off a outdoor house faucet or the mainline from your house before your house pressure regulator? If a hose faucet, then fill a five-gallon bucket and time how long to fill. Give us the time to fill 5-gallons. Next is the drip ones, how long or how many and what spacing and the type of drip lines or emitters? How many sprinklers and what Brand/type for each zone? What I am looking for is flow rates of drip tape or emitters to calculate the water demand for each zone. This is like a design in reverse which is a water audit. If you don't have all the info give me as much as you can. Finally, what is your water pressure? Buy an inexpensive pressure gauge that fits on your faucet from hardware store. When I can tell what zone uses what amount of what, then you can tell what zones can run simultaneously and the ones that need extra time can be at a later time and duration. You might try buying another Controller and hook three zone to one and 3 zone to another for the 6 programs you need. JMHO Aloha

10 liters, over 1 week's time, would be 16.8 hours per liter, or about 0.05 liter per hour, which is an incredibly tiny amount. I have never seen a drip control valve that could dispense that accurately at low pressure. You might be able to use a fiberglass wick at the bottom ... wick dries out and lets in a bit of air, some water gets released, wick gets wet and air stops for a while. Or insert the wicking through a hole in the side of the jug, to distribute the water slowly via capillary action. Although, as long as they are getting watered once a week with 10l or multiples of 10L, it shouldn't matter if the jug empties before the week is over, because the water is down there for the roots, and where it can't evaporate. Only very young trees, those in their first year, would need more frequent watering. I assume you are already using thick mulches to retain water? And using native, deep-rooted trees for optimal survival.

Hi tdscpa, Thanks for your suggestions. I had checked out the rainbird and other websites but I did not see explanations on having the manifold at the water faucet with the lateral lines going 25 feet underground verses having the main line going 25 feet under ground with the manifold in the irrigation area. But see my comments below. Hi homr, Thanks for taking the time to key in all that information. Especially explaining the pressure loss problems. But it looks like my whole plan will have to be revised due to what I learned. See my comments below. REVISED PLAN: Thanks to all who contributed to this thread. I really appreciate it. I talked to a city tech and he gave me a link to city ordinances which deal with irrigation systems. From what I read, it appears that the backflow preventer (BP) has to be installed in the main line prior to any branching. This means the BP will have to be installed near the front corner of our property where the main line first enters our property. This will require longer runs from the BP to the irrigation areas in the front and back yards. I'll have to check with a licensed plumber with experience in irrigation systems confirm whether the BP has to be installed before any branching. But it looks like I have even bigger problems if the BP has to be installed at the front corner of our property: 1. If the BP has to be installed at the front corner of our property, the main line will have to go across our concrete driveway and entry sidewalk to get to our front yard. IÂm reluctant to cut our concrete driveway and entry sidewalk to do this. 2. The path from the BP at the front corner to the back yard is all concrete. That side of the house has concrete from the house to the hollow tile perimeter wall. A DIFFERENT QUESTION: Any licensed plumbers reading this? Is there a universal code that says all main lines have to be buried in the ground? Or is it "generally" permissible to run a main line above ground? (Like attached to our hollow tile perimeter wall above the concrete sidewalk?) Assuming I can get the main line from the BP at the front corner to the back yard, I will have to run the line around the house (buried under ground) to get it to the front yard without having to do item-1. (The other side of the house does not have concrete.) Sorry for the long post. I guess there is no such thing as a simple drip irrigation system if it is to be done right, Sky