How do I clean rust stains off of vinyl siding?

There's a product called Spray and Forget

Its strong but it works n you can mix it with water in a bottle spray bottle...in a day or so u will see a difference

Simple Green, bleach, and a scrub brush.

If You have a pressure washer, that may work.

CLR or Krud Kutter should loosen. Then scrub and pressure wash. Make sure the water you use is "clean". You might have to hire someone to do it that has a portable tank.

This article suggests using Bar Keepers Friend cleanser.

https://bluecrystalsky.com/remove-rust-stains-vinyl-siding

You DO have a lot of rust! YIKES!

Rustoleum makes a great professional rust remover.

That is a lot of rust. You need something strong. Wet and Forget is a mold and mildew remover. Water softener doesn't control rust. You need a rust filter.

https://www.menards.com/main/paint/solvents-cleaners-removers/paint-preparation-cleaners/krud-kutter-reg-the-must-for-rust-32-oz/305982/p-1455229361507.htm

https://www.walmart.com/ip/Evapo-Rust-The-Original-Super-Safe-Rust-Remover-Water-based-Non-Toxic-Biodegradable-32-oz/38692066?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227026964012&wl0=&wl1=g&wl2=c&wl3=56093344209&wl4=pla-88700477049&wl5=9021620&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=38692066&veh=sem&gclid=EAIaIQobChMI-bmKm9HJ4wIVWiCtBh1-pAVEEAQYAyABEgJAJfD_BwE

https://www.google.com/shopping/product/11091014195554806529?lsf=seller:8740,store:3341704894885279178&prds=oid:14690308933257925424&q=rust+remover+menards&hl=en&ei=nEA2XY-EE4PY_wSy04DQBg&lsft=gclid:EAIaIQobChMI-bmKm9HJ4wIVWiCtBh1-pAVEEAQYCyABEgKoFfD_BwE,gclsrc:aw.ds

https://www.walmart.com/ip/Goof-Off-Rust-Remover-Gallon/21798693?wmlspartner=wlpa&selectedSellerId=1122&adid=22222222227016809915&wl0=&wl1=g&wl2=c&wl3=51754247591&wl4=pla-83159422991&wl5=9021620&wl6=&wl7=&wl8=&wl9=pla&wl10=101593696&wl11=online&wl12=21798693&veh=sem&gclid=EAIaIQobChMI-bmKm9HJ4wIVWiCtBh1-pAVEEAQYEiABEgJE4vD_BwE

We have a rust filter before the water comes into the house. Also a taste and odor filter for our kitchen. I wonder if you could adapt the rust filter somehow to filter your outside water.

our water comes into the house and splits off, part going to the house through a whole house filter and water softener, the other part goes directly to the underground sprinkling system. This might work. Thanks.

if you have a water softener, there are water softener pellets with iron remover added..well worth it.

The sprinkler water goes straight from the well. It does not go through the softener or house filter.