Heat the olive in a frying pan.
Finely dice the onion and garlic.
Add to the pan and cook on a low-med heat for 2 minutes.
Finely chop the capsicums and add to the frying pan, continue to cook for another 10 minutes, covered and stirring occasionally.
Add the passata, water and salt & pepper and continue to cook covered for 15 minutes.
Meanwhile, cook the pasta according to packet directions.
Remove the cover from the sauce and cook uncovered until the sauce thickens, about 5 minutes.
Drain the pasta and combine with the sauce before serving.