The main wastewater pipes in our street date back to the 1870s and an archaeologist is on site while they are excavated and replaced.
The lateral pipes (leading into each house) are more recent. The one into my house is dated at around 1920. The cap on it was replaced yesterday with a PVC one.

A neighbour who had problems with his pipes, was very relieved (excuse that dreadful pun) to have his 1940s pipe replaced, as it turned out to be broken – probably in the earthquakes.
The street which was repaired before ours (Ranfurly Street) yielded a stash of French champagne bottles which, the worker I spoke to believed, had been used (recycled) for home brew. They were found on the former site of a 16 hectare farm of which only the house remains.
This is fascinating stuff. It reminds me of the broken ancient (well, old) glass and crockery which has emerged from a corner of the garden near the street since new fences were built. It still comes up to the surface mysteriously from time to time. This is the most interesting of the crockery:

A recent exhibition at Tūranga, the main library, featured excavated items from the shops which used to line Gloucester Street. The post-earthquake rebuild of the central city and, lately, the construction of Te Pae, the convention centre, have kept archaeologists busy. China and glass fragments have been pieced together to give an insight into the past – what you might have seen if you had looked through the shop window.
The work on our street is only going as far as the intersection adjacent to our house. If they find original brick wastewater structures it will take longer to replace. So we may be in for more entertainment yet!