Rainwater tank water leaking

Sara thy · Jan 12, 2025 1:33 am

i can see water leaking here in downpipe from Rainwater tank. (arrow pointed in image below) Is it normal?
should there be a pipe attached to the spigot and inserted into the overflow pipe ?
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SaveH2O · Jan 12, 2025 2:02 pm

In your previous rainwater tank thread, I gave you a lot of advice which included in post 5:-

"FIRST FLUSH DIVERTER:
Never, ever allow a first flush diverter to be fitted at the top of a wet system's vertical riser at the tank. If it is, the first flush will only fill with the settled water retained in the vertical riser since the last rain event while the first flush will still be in the downpipe! A first flush diverter must be fitted to the downpipe when plumbing a wet (charged) system."

rainwater tank pvc or stainless steel • Home Renovation & Building Forum

What some dill has done is fit a tiny first flush diverter to the top of the vertical riser (the inflow pipe). The bottom of the diverter has a dripper on it which continually drains the water. This should be fitted with a small drain tube that ideally is connected to the overflow pipe but your diverter doesn't even have this.

Your photo of this endemic, bad installation practice actually demonstrates how much water is lost through the 'dripper'. 4-6 litres per hour is common but your 'dripper' most probably exceeds this. It drips faster when full and it would be interesting to know how long it takes to fill a 1 litre container during rain periods.

Just have the diverter removed, it is useless anyway. I can't help but feel angry when I see these endemic bad practices and it is hard to imagine that plumbers don't know better.

I also recommended:-
"Have a Rainharvesting brand Air Gap fitted to the overflow pipe so that the tank's overflow outlet's mesh, which restricts the tank's overflow capacity and which can also gum up, can be removed. This will reduce maintenance plus increase the tank's overflow capacity."

The above is best practice and should also be done.

Invariably, when there is one substandard installation, there will be others! Can you post a photo of the pump's suction hose and its connection to the tank and pump so I can check if it is all ok?

Sara thy · Jan 14, 2025 11:06 am

SaveH2O

In your previous rainwater tank thread, I gave you a lot of advice which included in post 5:-

"FIRST FLUSH DIVERTER:
Never, ever allow a first flush diverter to be fitted at the top of a wet system's vertical riser at the tank. If it is, the first flush will only fill with the settled water retained in the vertical riser since the last rain event while the first flush will still be in the downpipe! A first flush diverter must be fitted to the downpipe when plumbing a wet (charged) system."

rainwater tank pvc or stainless steel • Home Renovation & Building Forum

What some dill has done is fit a tiny first flush diverter to the top of the vertical riser (the inflow pipe). The bottom of the diverter has a dripper on it which continually drains the water. This should be fitted with a small drain tube that ideally is connected to the overflow pipe but your diverter doesn't even have this.

Your photo of this endemic, bad installation practice actually demonstrates how much water is lost through the 'dripper'. 4-6 litres per hour is common but your 'dripper' most probably exceeds this. It drips faster when full and it would be interesting to know how long it takes to fill a 1 litre container during rain periods.

Just have the diverter removed, it is useless anyway. I can't help but feel angry when I see these endemic bad practices and it is hard to imagine that plumbers don't know better.

I also recommended:-
"Have a Rainharvesting brand Air Gap fitted to the overflow pipe so that the tank's overflow outlet's mesh, which restricts the tank's overflow capacity and which can also gum up, can be removed. This will reduce maintenance plus increase the tank's overflow capacity."

The above is best practice and should also be done.

Invariably, when there is one substandard installation, there will be others! Can you post a photo of the pump's suction hose and its connection to the tank and pump so I can check if it is all ok?

thanks even i mentioned the above points to my builder, unfortunately the plumber did in the standard way.
now its all done.
i have attached full image of my 2K litre slimline water tank below
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SaveH2O · Jan 15, 2025 12:27 am

Thank you for posting the two photos.

PHOTO 1

I can see a power cord entering the tank where a charged pipe discharges its water.

I can also see a small pipe coming out of the tank at the same location. This pipe travels horizontally along the top of the tank and then rises vertically to connect to the bottom of an automatic mains water switching device.

The power cord will be connected to a submersible pump and the small pipe will transfer water from the pump to the mains water switching device.

UNPROFESSIONAL SUBSTANDARD PRACTICES
Of great concern:

The charged (wet system) inflow pipe that is discharging water into the tank from a height is directly above where the submersible pump is located inside the tank! :cry:

Unless the tank remains reasonably full, the falling water will resuspend sediments from the tank's floor where the pump is located plus the pump will often ingest air bubbles when the pump is operating while it is raining.

The worst case scenario is if the submersible pump sits on the tank's floor and draws water through a bottom suction intake. A submersible pump, so described, must be placed on a perforated platform 150-200mm above the tank's floor for several obvious reasons including not wanting the pump to vacuum the tank's floor.

If the pump has a higher suction intake or is connected to a floating intake, the pump can sit on the tank's floor but there would then be a greater chance of the pump more frequently ingesting damaging air bubbles if in use while it is raining.

You need to ascertain where the pump draws water to and, if it draws water in from the bottom, also check whether it has also been plonked on the tank's floor but the overriding number one concern is with the pump's incredibly bad location.

With the small pipe and the power cord passing through the tank, you also need to check whether the tank's mosquito proofing has been compromised.

A well designed charged rainwater harvesting system will be plumbed with a flush valve fitted at the buried pipe's lowest point or better still, with the simple sediment trap that I have designed to capture bedload. Without either of these being fitted, sediments will accumulate in the underground pipe and the water retained between rain events will become increasingly anaerobic due to the bacteria feasting on the organic smorgasbord causing oxygen depletion.

It is legislated in many regions for a charged system's downpipes to be fitted with leaf diverters to prevent organic and other detritus from entering a charged system. This should be mandated for all charged systems but unfortunately, it isn't. Regardless, any designer or installer should be knowledgeable enough to know that leaf diverters should be fitted at the downpipes. The only one that I recommend is the ICON Leaf and Debris Controller and I kid you not, that is what it is called! :-?