plastic drainage

[xraanswerban]

Hello, what year were plastic drainage introduced into the building trade.
The reason being, there is a plastic manhole on a property that serves three other properties, this plastic manhole blockes up quite often, the owner of the property denies that he installed this item even though he has to unblock the manhole.
It has been incorrectly installed so to find out when these items were first made will track down the culprit.
the owner insists that it's 1930s
thank you for any answers.

[pug100]

Hi,
This question may get a better response in Home & Garden rather than Technology.
A lot of houses in our area are 1930s semis they all have iron drain covers, I'd have thought plastic was a 1970s or 80s thing.

[xraanswerban]

Thank you pug100, now entered in Home and Garden.
Regards.
xraanswerbank