diff --git a/doc/guix.texi b/doc/guix.texi
index 456dfb264d..1069a5d296 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -19830,12 +19830,15 @@ configuration.
 @item @code{ident-file} (default: @code{%default-postgres-ident})
 Filename or G-expression for the user name mapping configuration.
 
-@item @code{socket-directory} (default: @code{"/var/run/postgresql"})
+@item @code{socket-directory} (default: @code{#false})
 Specifies the directory of the Unix-domain socket(s) on which PostgreSQL
-is to listen for connections from client applications.  If set to
-@code{#false} PostgreSQL does not listen on any Unix-domain sockets, in
+is to listen for connections from client applications. If set to
+@code{""} PostgreSQL does not listen on any Unix-domain sockets, in
 which case only TCP/IP sockets can be used to connect to the server.
 
+By default, the @code{#false} value means the PostgreSQL default value
+will be used, which is currently @samp{/tmp}.
+
 @item @code{extra-config} (default: @code{'()})
 List of additional keys and values to include in the PostgreSQL config
 file.  Each entry in the list should be a list where the first element
diff --git a/gnu/services/databases.scm b/gnu/services/databases.scm
index a841e7a50e..6ef3f3383c 100644
--- a/gnu/services/databases.scm
+++ b/gnu/services/databases.scm
@@ -115,7 +115,7 @@ (define-record-type* <postgresql-config-file>
   (ident-file        postgresql-config-file-ident-file
                      (default %default-postgres-ident))
   (socket-directory  postgresql-config-file-socket-directory
-                     (default "/var/run/postgresql"))
+                     (default #false))
   (extra-config      postgresql-config-file-extra-config
                      (default '())))
 
diff --git a/gnu/tests/guix.scm b/gnu/tests/guix.scm
index 219b8b482f..af7d8f0b21 100644
--- a/gnu/tests/guix.scm
+++ b/gnu/tests/guix.scm
@@ -164,10 +164,7 @@ (define %guix-data-service-os
                             "
 local	all	all			trust
 host	all	all	127.0.0.1/32 	trust
-host	all	all	::1/128 	trust"))
-               ;; XXX: Remove when postgresql default socket directory is
-               ;; changed to /var/run/postgresql.
-               (socket-directory #f)))))
+host	all	all	::1/128 	trust"))))))
    (service guix-data-service-type
             (guix-data-service-configuration
              (host "0.0.0.0")))
diff --git a/gnu/tests/monitoring.scm b/gnu/tests/monitoring.scm
index be69e1c259..8630f5818c 100644
--- a/gnu/tests/monitoring.scm
+++ b/gnu/tests/monitoring.scm
@@ -309,12 +309,7 @@ (define %zabbix-os
           (service dhcp-client-service-type)
           (service postgresql-service-type
                    (postgresql-configuration
-                    (postgresql postgresql)
-                   ;; XXX: Remove when postgresql default socket directory is
-                    ;; changed to /var/run/postgresql.
-                    (config-file
-                     (postgresql-config-file
-                      (socket-directory #f)))))
+                    (postgresql postgresql)))
           (service zabbix-front-end-service-type
                    (zabbix-front-end-configuration
                     (db-password "zabbix")))
diff --git a/gnu/tests/web.scm b/gnu/tests/web.scm
index cc0e79c8b2..7f4518acd2 100644
--- a/gnu/tests/web.scm
+++ b/gnu/tests/web.scm
@@ -569,12 +569,7 @@ (define (patchwork-os patchwork)
                (listen '("8080"))))))
    (service postgresql-service-type
             (postgresql-configuration
-             (postgresql postgresql-10)
-             ;; XXX: Remove when postgresql default socket directory is
-             ;; changed to /var/run/postgresql.
-             (config-file
-              (postgresql-config-file
-               (socket-directory #f)))))
+             (postgresql postgresql-10)))
    (service patchwork-service-type
             (patchwork-configuration
              (patchwork patchwork)