The Local Government Finance Act 1988 provides for non-domestic hereditaments to be revalued every 5 years. On a revaluation new non-domestic rating lists are compiled showing the updated rateable values of all hereditaments. The last compilation date was 1st April 2017. The Non-Domestic Rating (Renewable Energy Projects) Regulations 2013 (“the 2013 Regulations”) operate on the basis that any increase in rateable value from 31st March 2013 can be attributed to a change in the hereditament or its use. The effect of the revaluation is that, from 1st April 2017, hereditaments may have seen changes in rateable value compared with 31st March 2013 without there necessarily having been a change to the hereditament.
Link: The Non-Domestic Rating (Renewable Energy Projects) (Amendment) Regulations 2017
Source: Legislation .gov.uk