Some actual advice. First tell her there’s no need cleaning till she get’s her drainage fixed. It’s red clay stains. Can see on foundation of house next door and where mud has pooled up at bottom of walk coming from left. Go to HD or Lowes and get you about 5 gallons of Muriatic acid. Mix 1-3 or 1-4 . Make sure you add the acid to your water, not the other way. You can use xjet set properly also for larger job. Spray on, let sit for about 15-20min. Rinse off with decent pressure. Then I’d surface clean it. Make sure to use PPE.
