Rust colored pre filter-- Anyone else?--

[Oceanic]

I seem to be having a minor issue with my city water, I live in Langley and for the longest time the filters in my RO/DI would last months. Now my nice white pre-filter gets clogged up with a rust colored brown sludgy stuff within a few weeks. The wife is also noticing that she has to clean the toilets and shower more often due to the same rust colored sediment. Our house is only 4 years old in a newer neighborhood. Anyone else experiencing this?

I have to change the pre-filters all the time or the pressure drops and my water production drops down to nothing.