Water runs brown, any ideas?

[timbray]

My boat is a 2017 NC 795, very little used until I bought it in May 2019.  When it's been sitting for a while - just a day is long enough - if you turn on the faucet in either kitchen or head, after a second the water runs brown-ish for a couple of seconds.  I have thoroughly sanitized the system with chlorine bleach and flushed it multiple times, and the water actually seems clean, and tastes fine.

Given the cleaning effort and the color, I'm wondering if it's rust in the system, rather than biological contamination problem.  Before I start tracing the water system around and tearing things apart, I wonder if anyone has seen this problem.  Maybe it could be the filter system acting up?

[panoramix]

Brown looks like rust. In that case the previous owner might have installed some steel piping?

Pipes like used in a central heating system will color the water brownish within 24 hours.

[timbray]

After poking around online, it's been suggested that the problem is in the water filter. I found this helpful post which says it's easy to get the filter out, just pinch and it comes out.  I'm feeling kind of dumb, can't find anything pinchable. Looks to me like it maybe screws out?  Anyone have any advice on pulling apart the water filter so I can clean the inside?  Pictures below.  I believe the filter is the attachment on the lower left in the first picture.

[MalcolmP]

The cap of the filter should unscrew

Couldn't see the reference to pinching on the post you linked to, but suspect they are referring to disconnecting the Hep2O fittings on that check valve in shown in the image
 

These need to be squeezed to unlock as shown in video here:

[timbray]

Urgh. Wrong link.  Should be: sailingmareda.blogspot.com/2018/06/cleaning-jabsco-par-max-water-pump.html