I’ll add a ball valve to this existing bulkhead fitting. I first add a reducer down to one and a half inches. I didn’t have channel lock pliers big enough for these so I used the biggest wrench I had. Then I’ll add this short nipple, and then the ball valve.

Before I can add the float and screen I need to assemble the parts first. I BOUGHT some of the tank parts and decided to MAKE some of them from existing fittings.

I cut the float hose down to a length I though appropriate for the height of this tank. About 2 feet taller than the tank I thought would be good. There’s a barbed fitting that goes into the inside part of the bulkhead fitting first. Then the clear flexible hose goes onto that. It was a tight fit and tough to get this on, even with some soapy water as a lubricant. And a stainless steel hose clamps secures it.

Then the screen and float goes on the other end. And a lanyard is tied to the float. This will keep the screen up off the bottom of the tank when the water level gets low.

I’ll need to drill a hole in the tank for a bulkhead fitting for the hose that’s connected to this float. It will be around the back at the southeast corner. I’ll use a hole saw for this and drill this hole 4 about inches off the bottom.

Getting the bulkhead fitting through this hole can be tricky. I first screwed in a barbed fitting into the bulkhead fitting. Then I tied a string to the barbed end. And taped it too.

The other end of this string is taped to the end of a pipe.

Then this pipe is set in the tank with the string end resting on the hole I drilled. I then carefully remove the tape and pull the string through the hole.

I remove the pipe from the tank and lay in the hose and float assembly. Being sure that the end of the lanyard on the float is still outside.

I now pull the string to bring the bulkhead fitting through the hole and attach the nut. I snug this up with a wrench.

I’ll be connecting this fitting to the mini pump house later. But for now I’ll add a ball valve so I can make the tank water tight. I detailed the construction of the pump house box in Part 2.

To find the best spot for the tank inlet I sighted down a large speed square. I lined up one edge to the curb and marked the point where the 45 degree edge contacted the tank.

Then I can mark my center point for the inlet hole.

I marked this location this way so I could use standard 45 degree elbows to connect the pipe to the surround wall. I tried to position this hole as high up on the tank as possible. Not so high that it would not run into the thread lip where the lid screws on.

You don’t get a lot of second chances drilling holes in a big tank. So I took my time planning and thinking this through.

I used a large hole saw for the inlet and overflow pipes. On the slow setting, I drilled until the pilot bit pierced the tank, then clicked the drill in reverse to cut the big hole. This keeps the hole saw from grabbing. And this worked really well.

A rubber grommet fits in the hole and the pipe expands the rubber to make the seal against the plastic watertight. Then I push in a short piece of pipe. It’s tight and a bit of soapy water helps.

So that water entering the tank does not stir up sediment, I’ll run a pipe to the bottom with two elbows to create a calming inlet.

This will keep the water from splashing as the tank fills. I glue up a 90 and 45 fitting and attach it to one end.

Then add a 90 to the other end.

Then set this in the tank and attach it with a stainless steel screw. In case I need to remove it at any time later.

Now, I can drill the hole for the overflow siphon.

It’s just slightly lower than the inlet hole. And I needed it to rotated around this access hatch wall so it didn’t run into the inlet pipe.

Then a short piece of pipe is convinced strenuously that this is it’s new home.

For this tank overflow I’ll use standard fittings to create a siphon. It’s made from three 90 degree elbows and an angled pipe.

When the tank is full this siphon will skim water off the surface and send it down a pipe to the dry well that I dug in Part 1 of this series.

Now I’ll glue that in place.

You can buy a siphon formed from one piece but my suppler was out of stock. I think it works out to be cheaper than making your own when you add up the cost of the fittings. And there’s options without a siphon that use a simple 90 degree fitting with screen to keep mosquitoes out.

In case the siphon dries out I’ll add a screen on the pipe end that runs into the drain just in case. And that’s done later.

Next I’ll tie the tether for the float to one of the pipes to keep it off the bottom.

On the other side of the tank I’ll add a gauge. It’s a float on a spring coiled spool that you set to your low and high water points.

Now I’ll start to put together my assembly of fittings that will attach to the tank inlet. I bought a first flush diverter kit and need to adapt it to 3″ drain pipe.

The fittings it comes with are designed for the thicker Schedule 40 PVC pipe. The gate valve I’ll be also adding is designed for this thicker pipe.

So I need to first glue in these sleeves to allow me to connect everything together.

Let me stop for a minute to explain what I’m gluing up here. Water will first run into this angled downspout screen. This will help keep leaves and debris from the gutter from entering the tank.

Below that screen is a T fitting. With one of the outlets running into the first flush T.

Below is a gate valve that will connect to the drain pipe that goes to the dry well. When this gate valve is closed water will back up against the gate and then fill the first flush diverter before it finally ends up in the tank.

So the gate valve will be closed when I want to fill the tank. And it will be left open when I want water to bypass the first flush and tank inlet and instead go directly to the drain.

Stay with me here, it will become more clear as I attach this assembly to the fence surround.

Okay, moving on.

I could only find the black ABS adapter sleeves but they will work fine for this. I just need the right glue that works on PVC and ABS together. And you have very little time, a few seconds really, to get the parts in the right position once you glue them and slide them together. And there’s no going back for a second try. You can only guess how I learned this.

So I’ll glue these sleeves to the first flush T. Then to the gate valve. Then with short pipes I can attach the gate valve and T’s together.

I didn’t want all the plumbing and fittings hanging off a post on the pavilion. For one there wasn’t enough room and I didn’t think it would look so good.

Better in this case to keep it all close to the tank on the taller East wall of the surround.

This assembly is attached to the inside of the east wall using some brackets. A 90 degree elbow is attached to the outlet of the first flush diverter T. Then a pipe and fitting assembly is secured to the tank inlet pipe with rubber couplings.

For some of the plumbing here I tried to think about having to disassemble things later. So I only glued what I really needed to.

I like these 3″ flexible rubber couplings with the two screw clamps. They are great for quickly taking sections apart. And to manage tough connection points or those that require some flexibility. I’m not sure how they will hold up to sunlight over time so I may have to add some protection for them later.

Now I’ll add the downspout screen.

Here I’m adding another pipe and elbow section for the tank overflow. It will run into a Y fitting below the gate valve.

A length of schedule 40 pipe is glued into the first flush diverter T then a threaded section glued to the bottom of that. The diverter holds a ball, screen, and pinhole washer and this system is designed to catch the dirty water that is first coming off the roof when it starts to rain. I’ll add a link to a previous video of mine that explains this better.

Now I’ll glue up the pipe that runs around the back of the tank to the drain. It has a screened flapper end.

Finally I’ll run a pipe from the gutter of the pavilion to the tank surround. This will dump water onto the downspout screen.

This was a bit tricky to pull off. But it ended up working very well. Later I spray painted this pipe and fittings to match the brown gutter.

The last bit of plumbing to do here is to add a vent to the tank. For this I bought an RV tank vent and fitted it with a bug screen.

I cut a disc of aluminum window screen and siliconed it to the base of the vent.

I cut a hole in the top of the tank with a hole saw.

Added some silicone to the base of the vent and attached it with screws.

So I hope you have enjoyed this post, and thank you so much for reading. If I make any further improvements or changes I’ll post them here.

And, while you are here, please hit the Support Link to help us make more projects and videos like this. We really appreciate anything you can do to help us out!

Tools Used

Thank you for supporting us by using these affiliate links

Plumbing Fittings

• 3″ PVC Gate Valve
• 3″ PVC Sanitary Tee
• 3″ PVC 90 degree Elbow
• 3″ PVC 45 degree Elbow
• PVC Adhesive
• 3″ Bulkhead Rubber Grommets
• 3″ Rubber Coupling
• Spin Down Filter
• 12V Water Pump

Watertank Parts

• 1-1/2″ Ball Valve
• 1″ Ball Valve
• First Flush Diverter
• Downspout Leaf Catcher
• Float and Screen
• Tank Water Gauge
• Tank Vent
• Overflow Siphon
•  

Form Building / Woodworking

• Dewalt 20V MAX Compact Drill/Driver set
• Dewalt 20V Battery Charger
• 3lb Sledge Hammer for driving stakes
• 10″ Compound Miter Saw
• Hand Saw
• Screwdriver Set
• Large Speed Square
• Small Spirit Level
• Measuring Tape
• Driver Bit Set
• Circular Saw

Concrete Tools & Additives

• Flat Margin Trowel
• Flat Trowel
• Edger
• Wooden Mallet
• Mixing Bin

Drill Bits & Hole Saws

• Drill Bit Set
• 4″ Hole Saw
• 2-1/4″ Hole Saw

Solar Parts & Tools

• Solar Kit
• Fuse Block
• ANL Fuse Holder
• Shunt
• Deep Cycle Battery
• Wire Lugs
• Lug Crimper
• Wire Crimper
• Wire Terminals