Browse Forums Eco Living 1 Oct 07, 2021 6:13 am Just a quick question on where the rainwater pump should connect to the tank? The tank came with one outlet valve towards the base of the tank which is where it's currently plumbed into. Recently, we had some issues and the supplier came out and said the pump needs to be connected further up and the plumber should have drilled a hole in the metal tank to connect it to. He said this was to protect the pump from sucking in sediment. Which makes intuitive sense but then why wasn't there a 2nd hole in the tank? Looking online I can really only see the pump being connected to the outlet valve near the base of the tank, so that does seem the norm. Who right? The plumber or the supplier? Re: Rain water tank pump connection. 2Oct 07, 2021 9:09 am The pump supplier is correct. It is rare to find a rainwater tank installation that is not substandard and what you have described is an all too common substandard practice. Plumbers have no training in rainwater harvesting installations and numerous substandard practices are now endemic because most plumbers unthinkingly copy each other. A bottom outlet is a drain valve that draws the worst quality water and resuspended sediments from the anaerobic zone. The outlet valve supplying a pump should be a minimum 80mm to 100mm above the bottom of the tank at the valve's lowest point . Note that most manufacturers take the height of the outlet as being from the opening's mid point. You always need to stress how the valve's height should be measured. Supplying a pump from a drain valve is just one of several sub standard practices foisted on unwary and trusting homeowners. Check the list below that only refers to pumps..... 1. Fitting a pump to a drain valve at the bottom of the tank. The worst quality water is at the bottom of the tank. A dedicated valve supplying the pump must be fitted. 2. Fitting 25mm Blue Stripe poly pipe to a pump's 25mm suction port. Blue Stripe is measured as an outside diameter (OD), the true internal diameter (ID) of PN12 Blue Stripe is about 21mm. A 25mm ID pipe has 42% more volume than a 21mm ID pipe and most manufacturers will void the pump's warranty as per their warranty conditions if the pump is found fitted with an undersize suction hose. If a long suction hose is required, it is strongly recommended that the one used is one size larger than the pump's suction port. 3. Fitting a 90 degree elbow to the pump's suction port. The suction hose should respect 8 IDs of straight length at the suction port and most pump manufacturers state this it their warranty. Some manufacturers however state 5 IDs while others refer to a straight length distance which is commonly 200mm to 250mm. 4, Optioning the tank with the top meshed inlet dropping water in the vicinity of the tank's valve that supplies the pump. This results in:- (a) Sediment resuspension and turbidity in the outlet's vicinity when the tank's water level is low. (b) Air bubbles being drawn into the pump due to water being drawn via an upward flow path. This is the reason why a free surface vortex forms when the water level drops to critical submergence levels, a level that varies with the velocity of water flowing through the tank's outlet. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ 5. Failing to provide cross ventilation to the pump's cover to protect it from heat build up, a prime cause of capacitor failure. 6. Optioning an oversized pump. You don't need a powerful pump to supply a cistern or washing machine which are both slow fill end fixtures. 7. Fitting small diameter pipes between the pump and a garden tap. Read this thread... viewtopic.php?f=35&t=61588 8. Fitting pumps and mains water switching devices with copper pipe. Rainwater is naturally acidic, particularly during thunder storms and standing acidic water corrodes copper pipe. If the water is for potable use, the ppm of disolved copper can easily exceed the Safe Drinking Water guidelines. 9. Sometimes copper pipe is also exposed to the sun. Copper pipe exposed to the sun should be lagged. The regulations state that cold water must not be delivered to an end fixture at a temperature exceeding 40 degrees Celcius. 10. Many submersible pumps draw water in from the bottom of their casing, see photo at bottom. A failure to place these pumps above the sediment layer will see the pumps spend their life vacuuming the tank's floor. The best quality water is found 200mm below the water surface and this can be accessed by fitting a Floating Intake Filter to a hose that connects at one end to the outlet supplying the pump and is tethered at the other end to a buoy that keeps the filter 200mm below the surface. I plan to commercialise one that is substantially better and cheaper than all the others currently on the market. It is currently planned to offer the choice of 200 or 400 micron filtration. It sounds like the issues that caused you to contact the pump supplier were caused by sediment build up. A rainwater harvesting system designed for best practice delivers good quality water with minimal sediments to the tank and the best quality water in the tank then delivered to the pump. If you want to post some photos of the installation, I will identify any sub standard issues and offer remedies. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Can a plumber put a tap on a rain water tank which is full? Tank is similar to one in photo. 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