Decks, Patios, Porches and Docks - Azek

I am going to have an Azek porch installed to an old Victorian house with a wide covered porch surrounded by big trees.

This will be the Azek porch tongue & groove board. The porch sides are solid. In order to have drainage, the contractor will slant the boards (like my current wood porch) and leave a gap at the end between the board and siding - about 1/2 " - and not visible.

My concern is this - the porch will still have many (wet) leaves in Fall and snow in Winter sitting on it for a while. My fear is staining. I know Azek is advertised as being stain resistant, even for leaves, and their website has the "double dare" to show this.

What is reality? Should I expect no stains from leaves or snow? Or will this stain? If wood, you can paint away stain, but Azek you do not paint.

How do I prevent staining, if any - powerwash each Spring? Or? How do I lock into the warranty no big water or leaf staining, if possible?

I should add, I saw a porch near by that was similar to mine with what looks like Azek, and had what looked like a large water stain across the back half of it. It was decking boards with space between the boards but no slant. This made me worry, and my contractor is going to look at it and tell me if it is Azek or something that just looks like it.

Of all of the Azek (or Pro Cell, before Azek took them over) decks that I've put down (about 15 or 20 of them), none have a leaf or water stain on them. One did get some citranella wax spilled on it, and it sat for a couple of years. Simple Green took that right off.

A cleaner will work better than powerwashing. And if you simply sweep or hose the leaves off before they have a chance to sit on the porch for several weeks, staining won't be an issue.

Thank you ! Is there any particular cleaner?

Simple Green seems to do the best on just about every kind of dirt or stain that I've come across.

2nd that...Simple Green and Krud Kutter are the two I use for everything.