Normally, drip is a one-way transfer of water. Your faucet supplies water to the drip emitters, which let out water at a controlled rate. I wanted a slower water delivery, but could not reduce the water pressure enough, so I connected my drip system to a solar fountain pump.

Supplies

Aside from 1/4 inch drip tubing and a bucket, I use a solar powered "birdbath fountain pump" and a float valve.

These pumps are meant for decorative small fountains in birdbaths, and are not very strong. Keep that in mind when designing your system. Performance will drop off after a few weeks, so don't ask for too much pressure from them.

Step 1: General Setup

From the cover diagram, you can see that I buried a bucket below the level of the drip tube emitters. This prevents the tubing from siphoning the water out of the bucket. Inside the bucket is a float valve connected to the faucet, which keeps the water level consistent.

The solar fountain pump is submerged, and connected to a length of 1/4" drip tube. This tubing fits exactly into the pump's output port, which is convenient. The solar panel is mounted so it receives sunlight most of the time, and the pump will run whenever sufficient light is available. These pumps have no batteries, and so will only run in bright daylight.

Water pumps out of the bucket to the drip emitters, where it drips out at low pressure. The delivery is much less than you get at conventional household water pressure, or even when a pressure regulator is installed, but is more than adequate for my needs. Excess water that is not dripped out returns to the bucket. Overall, very little water is consumed by this system. In the picture, you can see a bit of water dripping from the tube. I like to cover the whole thing with mulch, to reduce evaporation from the soil. This also prevents a lot of clogging from mineral buildup.

It is self-regulating! During the night, the pump is off. During cooler overcast days, the pump runs only intermittently.

Step 2: The Bucket Sump

This bucket is sunk into the ground, and the water level is kept below ground level.

All of the components are labeled. Water consumption may be monitored a bit by watching the output of the float valve. If you see excessive water being sent into the bucket through the float valve, there is a leak in the system (e.g. a drip tube is disconnected and water is being lost excessively).

I have the bucket under a wooden cover to minimize light, so there is no algae growth. Algae can foul the pump, and so should be avoided. A biofilm may also form on the pump impeller, reducing performance. The pump should be periodically disassembled and cleaned.

Step 3: The Solar Panel

This little panel powers it all. I made a post for it to sit on, so it is not shaded by the house. I do not bother cleaning it at all, and it's still sufficient for my needs.

Step 4: Reducing Water Delivery

This is set up in a dishpan for clarity. The pump output tube can be connected to a "T" joint to let excess water drain directly back into the sump, if there's too much water being delivered. You can see the return tube here as well. The objective is to have an open system that delivers water at a low rate.

One pump system like this is supplying baseline water to four grapevines and two dwarf fruit trees. I occasionally give them all a soak using a hose, but otherwise they always have a bit of water to work with.

If you are concerned about the roots favoring the surface of the soil, making them vulnerable to sudden drying, just have the drip tubing deliver some water to a pipe that is driven into the ground so the drip can run down to a lower level.