Rent a pressure power washer, easy fun chore to do on a hot day. All you need is a garden hose and an outdoor spigot. It should take the paint off the deck without a problem.

Powerwash it.

Powerwash and then buy the bleaching agent. Some of the knots may require sanding or liquid stripper. Powerwash and see what you have to work with before committing to sanding or stripping.

Pressure treated wood can take stain, but not solid wood stain (that's what they used on your deck). Unfortunately, it fades out after about two years, so you redo everything anyway.

Remember: medium tones hide dirt better than light or dark tones.

It looks like the brown is paint, not stain, i've never seen stain chip like that. If its a more paint like substance then I am not sure that powerwashing would help, it may need to be stripped.

Yeah, that looks like paint to me. And painting over stain generally leads to the paint peeling, so that makes sense (unfortunately). Powerwashing might help, and will likely take a lot of paint off, but grab a scraper, too.

we just did this to our fence..powerwashing got most of it off (took some time!), & scraping did the rest

i just researched this very topic heavily, and ended up doing this with my own deck.

We've now painted it in colors that match our house (instead of wood tones) and it looks fabulous. Took a few steps but it's worth it!

We have a weatherboard house just like the one in the picture, (ours is cream with charcoal trim) and we painted the deck beams and posts cream, and the deck itself charcoal. It now looks like an integral part of our house rather than "random exterior addition".

We used special Decking paint for the deck floor.

Hope this helps anyone else who wants to do this!