diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 87947e604..3b3aa034b 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -97,7 +97,6 @@ jobs:
             POSTGRES_CUSTOMER_CAS_CONNECTION_NAME:${{ vars.GOOGLE_CLOUD_PROJECT }}/POSTGRES_CUSTOMER_CAS_CONNECTION_NAME
             POSTGRES_CUSTOMER_CAS_PASS:${{ vars.GOOGLE_CLOUD_PROJECT }}/POSTGRES_CUSTOMER_CAS_PASS
             POSTGRES_CUSTOMER_CAS_DOMAIN_NAME:${{ vars.GOOGLE_CLOUD_PROJECT }}/POSTGRES_CUSTOMER_CAS_DOMAIN_NAME
-            POSTGRES_CUSTOMER_CAS_INVALID_DOMAIN_NAME:${{ vars.GOOGLE_CLOUD_PROJECT }}/POSTGRES_CUSTOMER_CAS_INVALID_DOMAIN_NAME
             SQLSERVER_CONNECTION_NAME:${{ vars.GOOGLE_CLOUD_PROJECT }}/SQLSERVER_CONNECTION_NAME
             SQLSERVER_USER:${{ vars.GOOGLE_CLOUD_PROJECT }}/SQLSERVER_USER
             SQLSERVER_PASS:${{ vars.GOOGLE_CLOUD_PROJECT }}/SQLSERVER_PASS
@@ -126,7 +125,6 @@ jobs:
           POSTGRES_CUSTOMER_CAS_CONNECTION_NAME: "${{ steps.secrets.outputs.POSTGRES_CUSTOMER_CAS_CONNECTION_NAME }}"
           POSTGRES_CUSTOMER_CAS_PASS: "${{ steps.secrets.outputs.POSTGRES_CUSTOMER_CAS_PASS }}"
           POSTGRES_CUSTOMER_CAS_DOMAIN_NAME: "${{ steps.secrets.outputs.POSTGRES_CUSTOMER_CAS_DOMAIN_NAME }}"
-          POSTGRES_CUSTOMER_CAS_INVALID_DOMAIN_NAME: "${{ steps.secrets.outputs.POSTGRES_CUSTOMER_CAS_INVALID_DOMAIN_NAME }}"
           SQLSERVER_CONNECTION_NAME: "${{ steps.secrets.outputs.SQLSERVER_CONNECTION_NAME }}"
           SQLSERVER_USER: "${{ steps.secrets.outputs.SQLSERVER_USER }}"
           SQLSERVER_PASS: "${{ steps.secrets.outputs.SQLSERVER_PASS }}"
diff --git a/tests/postgres_test.go b/tests/postgres_test.go
index 582da87e9..a2825c352 100644
--- a/tests/postgres_test.go
+++ b/tests/postgres_test.go
@@ -27,15 +27,14 @@ import (
 )
 
 var (
-	postgresConnName                 = flag.String("postgres_conn_name", os.Getenv("POSTGRES_CONNECTION_NAME"), "Cloud SQL Postgres instance connection name, in the form of 'project:region:instance'.")
-	postgresUser                     = flag.String("postgres_user", os.Getenv("POSTGRES_USER"), "Name of database user.")
-	postgresPass                     = flag.String("postgres_pass", os.Getenv("POSTGRES_PASS"), "Password for the database user; be careful when entering a password on the command line (it may go into your terminal's history).")
-	postgresDB                       = flag.String("postgres_db", os.Getenv("POSTGRES_DB"), "Name of the database to connect to.")
-	postgresIAMUser                  = flag.String("postgres_user_iam", os.Getenv("POSTGRES_USER_IAM"), "Name of database user configured with IAM DB Authentication.")
-	postgresCustomerCASConnName      = flag.String("postgres_customer_cas_conn_name", os.Getenv("POSTGRES_CUSTOMER_CAS_CONNECTION_NAME"), "Cloud SQL Postgres instance connection name for a customer CAS enabled instance, in the form of 'project:region:instance'.")
-	postgresCustomerCASPass          = flag.String("postgres_customer_cas_pass", os.Getenv("POSTGRES_CUSTOMER_CAS_PASS"), "Password for the customer CAS instance database user; be careful when entering a password on the command line (it may go into your terminal's history).")
-	postgresCustomerCASDomain        = flag.String("postgres_customer_cas_domain", os.Getenv("POSTGRES_CUSTOMER_CAS_DOMAIN_NAME"), "Valid DNS domain name for the customer CAS instance.")
-	postgresCustomerCASInvalidDomain = flag.String("postgres_customer_cas_invalid_domain", os.Getenv("POSTGRES_CUSTOMER_CAS_INVALID_DOMAIN_NAME"), "Invalid DNS domain name for the customer CAS instance.")
+	postgresConnName            = flag.String("postgres_conn_name", os.Getenv("POSTGRES_CONNECTION_NAME"), "Cloud SQL Postgres instance connection name, in the form of 'project:region:instance'.")
+	postgresUser                = flag.String("postgres_user", os.Getenv("POSTGRES_USER"), "Name of database user.")
+	postgresPass                = flag.String("postgres_pass", os.Getenv("POSTGRES_PASS"), "Password for the database user; be careful when entering a password on the command line (it may go into your terminal's history).")
+	postgresDB                  = flag.String("postgres_db", os.Getenv("POSTGRES_DB"), "Name of the database to connect to.")
+	postgresIAMUser             = flag.String("postgres_user_iam", os.Getenv("POSTGRES_USER_IAM"), "Name of database user configured with IAM DB Authentication.")
+	postgresCustomerCASConnName = flag.String("postgres_customer_cas_conn_name", os.Getenv("POSTGRES_CUSTOMER_CAS_CONNECTION_NAME"), "Cloud SQL Postgres instance connection name for a customer CAS enabled instance, in the form of 'project:region:instance'.")
+	postgresCustomerCASPass     = flag.String("postgres_customer_cas_pass", os.Getenv("POSTGRES_CUSTOMER_CAS_PASS"), "Password for the customer CAS instance database user; be careful when entering a password on the command line (it may go into your terminal's history).")
+	postgresCustomerCASDomain   = flag.String("postgres_customer_cas_domain", os.Getenv("POSTGRES_CUSTOMER_CAS_DOMAIN_NAME"), "Valid DNS domain name for the customer CAS instance.")
 )
 
 func requirePostgresVars(t *testing.T) {
@@ -278,39 +277,6 @@ func TestPostgresCustomerCAS(t *testing.T) {
 	}
 }
 
-func TestPostgresCustomerCASInvalidSAN(t *testing.T) {
-	if testing.Short() {
-		t.Skip("skipping Postgres integration tests")
-	}
-	requirePostgresVars(t)
-	if *postgresCustomerCASPass == "" {
-		t.Fatal("'postgres_customer_cas_pass' not set")
-	}
-	if *postgresCustomerCASInvalidDomain == "" {
-		t.Fatal("'postgres_customer_cas_invalid_domain' not set")
-	}
-
-	defaultDSN := fmt.Sprintf("host=localhost user=%s password=%s database=%s sslmode=disable",
-		*postgresUser, *postgresCustomerCASPass, *postgresDB)
-
-	tcs := []struct {
-		desc string
-		dsn  string
-		args []string
-	}{
-		{
-			desc: "using invalid customer CAS domain (not in SAN)",
-			args: []string{*postgresCustomerCASInvalidDomain},
-			dsn:  defaultDSN,
-		},
-	}
-	for _, tc := range tcs {
-		t.Run(tc.desc, func(t *testing.T) {
-			proxyConnTest(t, tc.args, "pgx", tc.dsn)
-		})
-	}
-}
-
 func TestPostgresHealthCheck(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping Postgres integration tests")