If you chose not to report, you would follow the commentary for ECOA 1002.13(a)5
An application for an open-end home equity line of credit is not subject to this section [information for monitoring purposes] unless it is readily apparent to the creditor when the application is taken that the primary purpose of the line is for the purchase or refinancing of a principal dwelling.
Some comments from HMDA GIR
Home equity lines of credit (HELOCs)for home purchase or improvement may be reported at the institution’s option.
d. If you opt to report homeequity lines of credit, report only the portion of the line intended for home improvement or home purchase.
An institution that opts to report home-equity lines reports the disposition of all applications, not just originations.
I survived an OCC Fair Lending/Comparative File Review of 1,756 loans with no findings that stuck!
CRCM, CIA, CRP, CBA