[Andrew44]

Just set-up 4040 RO, all working well and getting about 12 TDS pre DI can.  Just had a check of rain water that collected in plastic container that was outside and it was reading.......8.2 !!  Had a few more checks of other areas of rain water and showing about 8.

Is the exceptionally low for rain water and is it low because of bad weather ie air purier after storms etc.

If it is consistantly low as this wouldn't it be better to water harvest and pump water from raon water containers through DI into IBC ..avoid RO alltogether???

[L.Doubtfire - The Blade Runner]

Exactly Andrew,having said that it is possible to catch and harvest rainwater
At 000ppm.It can be `fiddely`and time consuming depending on your catchment
System.Is anyone else catching rainwater at 000tds. Thanks

[Andrew44]

I've searched for 'rain water tds' on this site and this topic has come up before.  Looks like there is 120,000 ltrs of rain water falling on average semi each year and tds from down pipe after roof is 50 ish.  I may well get IBC positioned under outside tap (source of water) and feed down pipe into IBC and feed into RO (got pump).  This will dillute my tds readings from current tap of 330 with 50 tds rain water from roof.   I will need to top up with tap but this may get me 1/3 of the eater i need free and save on RO memberane and resin??

Woth a look I think.