Q - Want the best pressure and to fill without overflowing the barrels. Q - One barrel is sealed and one is not - which goes where? A – Drill a hole at the top of the sealed barrel to allow air in and out. Q - Right now have about 8' difference in height.should they be even? A – The tops of the barrels must be even. A – All connections to the barrels should be at the bottom.The pressure you get from the barrel increases if you elevate the barrel with a stand. For best pressure seems like bottom would be best. Do I want to connect together on bottom or top. Have a diverter that can overflow in 3x4 pipe and connected with hose to top of first barrel. This greatly reduces what needs to be done to a barrel to use it as a rain barrel. Each barrel requires only a small hole at the top to allow air in and out and a male hose connection at the bottom. Rain barrels can be positioned at a higher point on the property by moving the diverter higher on the downspout eliminating the need for a stand. Rain barrels no longer need to be located near downspouts so they can be positioned out of sight and away from buildings. The bottom filled design takes away the need to have an always down pathway like a stream from the downspout to the rain barrel. The tee has a built in valves that can be used to isolate barrels Rain barrels can be positioned away from the downspout with a long hose running on the ground. Can be implemented with common garden hose hardware designed for higher water pressure (reliable) Easy to expand to use more barrels (add tee and extension hose) Barrels do not need a large hole in the side for overflow Barrels do not need a large hole in the top for water intake I am sure the small diameter of the hoses I have used restricts the fill rate somewhat but after a rain event the barrel is usually full. Larger 5/8' hose connections may increase the water capturing efficiency but you will need all of the components including the connection to the barrel to be 5/8' in order to achieve the added efficiency. Multiple barrels can be added using additional tee connections. It is also handy to use a hose tee with shutoffs so you can isolate barrels, watering hose or the diverter.

You will also need a small extension hose to connect the tee to the rain barrel. I used the cheap rubber connection hoses that came with the our washing machine. The connection from the diverter requires a hose with two female connections, I used a connection hose from a washing machine because it is a good length and it has two female ends. In this application the pressure is unlikely to exceed 1psi so it provides very reliable connections between the barrels and the downspout diverter. Regular garden hose is designed to for pressures exceeding 100psi.

Down spout diverter for rain barrel