[richard jagger]

I have heard so much abut 3 monthly which is not exactly true. It would depend on how much water passes through these filter and what the nature of the particle solids are. The truth of the matter is when the flow rate drops . Anyone agree with this view.

[steven ainger]

i change mine every 6 months,  & my water is like soup 
have been doing it this way for the past 6 yrs

[R.C Property]

Change prefilter 6 monthly at the moment, but have had my ro membranes in for 2.5 years now, water has only gone up 002ppm in that time from putting them in till now!

[Ian101]

About every 4 months and Im producing about 6000 litrs a month so filtering 12000 litres

[Window Washers]

I change when they slow down I flush daily it works out about. 6 monthly same membrane for years tds in the 400's from tap that's 20inxh prefilter a used to change monthly when they where. 10inch was a lot cheaper back them forb10 inch prefilters about £1 odd each