Look at the Fair Lending examination manuals. The following is from the OCC's - others are the same.
4. Identify Residential Lending Discrimination Risk Factors
Review the lending policies, marketing plans, underwriting, appraisal and pricing guidelines, broker/agent agreements, and loan application forms for each residential loan product that represents an appreciable volume of, or displays noticeable growth in, the bank’s residential lending.
P7 *A loan program that contains only borrowers from a prohibited basis group, or has significant differences in the percentages of prohibited basis groups, especially in the absence of a Special Purpose Credit Program under the ECOA.
Explicit demarcation of credit product markets that excludes metropolitan statistical areas (MSAs), political subdivisions, census tracts, or other geographic areas within the bank’s lending market or CRA assessment areas and having relatively high concentrations of residents of a particular racial or national origin group.
Policies on receipt and processing of applications, pricing, conditions, or appraisals and valuation or on any other aspect of providing residential credit that vary between areas with relatively high concentrations of residents of a particular racial or national origin group and those areas with relatively low concentrations of residents of such racial or national origin group.
Advertising patterns or practices that a reasonable person would believe indicate prohibited basis customers are less desirable.
Advertising only in media serving particular racial or national origin areas of the market.
Marketing through brokers or other agents that the bank knows (or has reason to know) would serve only one racial or national origin group in the market.
Use of marketing programs or procedures for residential loan products that exclude one or more regions or geographies within the bank’s assessment or marketing area that have significantly higher percentages of residents of a particular racial or national origin group than does the remainder of the assessment or marketing area.
*Proportion of monitored prohibited basis applicants is significantly lower than that group’s representation in the total population of the market area.
Bec - taken individually, there may not be an issue, taken collectively, there may be. The list can go further. Remember that disparate impact includes the "effects test".
From the exam manual, "When a bank applies a racially or otherwise neutral policy or practice equally to all credit applicants, but the policy or practice disproportionately excludes or burdens certain persons on a prohibited basis, the policy or practice is described as having a “disparate impact.” Disparate impact has been referred to more commonly by the OCC as “disproportionate adverse impact.” It is also referred to as the “effects test.”
Integrity. With it, nothing else matters. Without it, nothing else matters.