I was sure to check on him a few times, in the six hours he took to finish the job. Just to make sure he hadn't passed out. I also offered cool drinks if required. But he came prepared. I still had to ask though.
Trench for the underground pipe
The last job we had to get done, before he arrived, was to dig the trench for the return line, up to our existing tank, and pump. He explained, both tanks would be drawn from, at the same time. Which was meant to be better for the tanks, than emptying one at a time. The plastic walls should have less chance of sagging inwards, as the water levels in both tanks, drop together.
As we were waiting days for the plumber, with trenches in the ground, we had to prepare for the possibility of rain. Which we DID receive. More about that soon. So we had to install a temporary hose in the overflow pipe of the old tank. Which is the black plastic you see.
Next to it, is a couple of old 2x4's used as a temporary bridge. It was much safer crossing a sturdy surface, than stepping over a large gap in sometimes soft, terrain. But what about that rain we received?
Outlet brass fitting
It was quite a big storm, and the trenches filled. The above picture was taken before the storm. It was on the day the tank was lowered into it's final resting place. Can you see where this is going? Trenches, water flowing and an open hole into the tank, at trench level.
I bet you can guess we had some soil deposited near the brass outlet? It didn't enter the tank, thankfully. It spilled onto the blue crusher dust though. I bet you couldn't guess that somehow, a thin veneer of water in the hole, was able to shift an empty, 450kg tank? Well, I certainly didn't believe it when I first saw it. The brass outlet fitting, that was facing centre of the trench (above) shifted, to face the edge of the trench instead.
I was too busy trying to fix it the next day, to get photographs, but this is what it looked like afterwards. I had to reposition the trench (as seen by the darker soil) so the brass fitting, was centre of the trench again. And as we had several more days to wait for the plumber, with more rain predicted, I rigged up a piece of board and log, to seal the brass fitting. It would also stop any water and silt, caught in the trench, draining into the hole the tank was sitting in.
We did get another rain event, but it wasn't as much as the first. So not a lot of silt travelled, and thankfully, the empty tank didn't move again.
Trench to pump
Back to the trenches though. Once our long trench passed the two tanks, and went up the hill, we curved it around to the pump. Our reliable Onga pump, has been going since 2007. It had a small repair early in the piece, but was covered under warranty. It has been running faithfully ever since.
You can see the bricks we had to install, under the pump, after our first big rain event. There's a reason for that. A lot of water escaped the tank through the inspection hole, just above the pump. It subsequently washed the soil out, and left the pump hanging only by it's copper pipe. Having a plinth of bricks go under ground, would help prevent this, should the soil wash away again.
Here is a picture of how it happened.
The roof of the tank is not meant to be that round! This was a result of dodgy plumbers, hired by our building company. There are two very specific reasons this happened, and could have been prevented. Firstly, there were two pipes going into the tank (from the roof of our house) and only one pipe to allow excess water, to escape a full tank.
In other words, too much going in and not enough pipe to let the excess water out. The pressure mounted and the water naturally burst through, where it could.
Outlet pipes connecting tanks
Our new plumber helped to solve this problem, by installing two pipes into the new tank, subsequently matching the amount of water entering from the roof. The plumber also installed an expansion joint in the overflow pipes. So as the new tank settles, it has a little leeway to move without affecting the pipes.
The second reason our old rainwater tank, risked bursting at the seams in big rain events, was the kind of overflow fitting, the plumbers used on the outlet pipe. This outlet pipe is designed to allow excess water to escape a full tank. Dodgy plumbers & Co, installed a fixed outlet pipe. Meaning, we couldn't remove the wire mesh, to prevent mosquitoes accessing the tank.
Picture taken, June 2016
we previously rigged a temporary pipe to take water away
from the base of the old tank
Why would we want to remove the mesh preventing mosquitoes access? So all those plastic shavings inside the tank, as a result of the plumbers drilling holes into it, could escape.
All those filings were blocking the outlet pipe from draining at full speed. Cheap and nasty plumbing solutions. There should have been a removable mesh cap on the overflow pipe.
New inspection joint
Needless to say, when our new plumber provided a different solution, when he came to quote, he got the job straight away. He was going to install a little device in the overflow pipe, which would allow us to clean the outlet pipe, of all the plastic filings he'd put into the tank. Makes perfect sense, doesn't it?
In the outlet pipe, there are removable mesh caps, above and below. They are easy to remove and more importantly, ensure that any overflow water, once both tanks are full, won't be blocked by plastic shavings. It's our job to remove the wire mesh, and clear it - especially the first time it overflows.
We still need to backfill at rear
Look what a professional job he did though. Not only is the overflow pipe going underground, and won't be released some 3 meters away from the base of the tank, but he also provided a plastic black box, for the tap and valve to be housed safely.
Access box to main valve
The pipe coming out of the tank, has a return valve, so the tank should never run dry and put air bubbles into the pump. When that happens, you have to re-prime the pump again. Which our friendly plumber showed me how to do, even though it was 38 degrees Celsius and he installed a return valve, so I shouldn't have that problem anyway.
He installed the return valve as a precaution, as he wasn't going to assume the plumbers who installed the first tank, installed a return valve. The first tank was partly buried, and from what pipes he had to access underground, he couldn't see a return valve. They could have put it lower down, but from where he had to access, he couldn't see it.
Technically, they should have installed a return valve, but he was rightly protecting his own workmanship, by ensuring any additions he plumbed in, wouldn't run into that problem, if the former plumbers didn't do their job properly. Which is really a sign of a professional, who takes their own workmanship seriously.
Water outlet, released down hill
Another feature, which won him the job with us, was taking the overflow water away from the base of the tank. Three metres away (all underground), and he even installed a grate so nothing could get in. The soil you can see on the grate box, was from the last storm. It came the very next day, and even though the plumber had installed everything the day before - he didn't have a spare grate in his truck.
He promised to pop around, the next day (a Saturday) on his way to a family gathering, to glue it on for us. He literally beat the storm, only by a few minutes.
I was really impressed with his workmanship, and ability to explain every step of the process. The fact we were doing the earthworks, ensured he had to explain various features, so we could implement the correct work. However, he made sure we understood all the pieces we weren't involved with either. If you're a local, then I can't recommend Ken Ball Plumbing, highly enough.
Backfilling crusher dust
One last job for us to do now, is finish backfilling the tank with crusher dust. And of course, because we love to garden, some new plants around the tanks. There will be rhyme and reasons for our selections of plants, which I look forward to sharing another time.
While the recent storm we received, wasn't able to fill both tanks, it did give us extra water to shift to the emptier tank. We were advised the tank should be at least a third full, before commencing backfilling. This ensures it won't be moved by any pressure we exert against it, dumping more crusher dust.
So, yay! Most of the incredibly hard yards and uncertainty about the second tank, have been settled. If you're interested in the numbers, here's the breakdown:
- Tank on sale, including delivery - $2,450
- Plumber (labour, parts, travel) - $1,560
- Crusher dust (supply, delivery) - $ 300
- Compactor hire (half a day) - $ 65
Which works out at 81 cents per gallon, or 21 cents per litre.
Before there were trenches, there was a hole to dig
Doing the earthworks ourselves, using only manual tools, saved us from $1,000 and possibly more. In fact, we were pleasantly surprised by the plumbers comments, after he installed the overflow pipes, between both tanks. He used his spirit level and said they were spot on, level. Coming from a professional, that meant a lot to us. We did our best to get them even, and spent extra time making it so, but to hear that confirmation, unprompted, was reassuring.
Perhaps we're not just a couple of crazy people, who like to suffer unusual punishment, digging relentlessly for months! Maybe it gives us a sense of satisfaction, after all the money gets exchanged, that we weren't just consumers shafted to the sidelines of our purchase. We've been honing skills, ever so gradually, over the years, and we hope to put them to good use in other projects in future too.
But for now...rest and gratitude.