There are levadas everywhere around Madeira, but did you know that you can find them inside Funchal too? This levada starts right next to the Maritimo football stadium and ends all the way in the mountains. 
The levada is safe with beautiful views to Funchal as you go along. Depending on how far you want to walk, you can walk at around 8-9 km before it gets dangerous. Unless you don't suffer from vertigo, you should turn around right after you get the place as pictured, where you crawl/bend walk. 
We usually walk until the levada starts going inland. 

Watch our full video from this levada here: https://www.youtube.com/watch?v=HQ5rx2X4xWs

Along the way you can stop for a cold beverage at Casa da Levada: 
https://www.tripadvisor.com/Restaurant_Review-g189167-d10814689-Reviews-A_Casa_da_Levada-Funchal_Madeira_Madeira_Islands.html