diff --git a/lib/builder.rb b/lib/builder.rb
index 10c76810..13434d28 100644
--- a/lib/builder.rb
+++ b/lib/builder.rb
@@ -227,7 +227,11 @@ class CustomWizard::Builder
 
   def validate_field(field, updater, step_template)
     value = updater.fields[field['id']]
-    min_length = field['min_length']
+    min_length = false
+
+    if is_text_type(field)
+      min_length = field['min_length']
+    end
 
     if min_length && value.is_a?(String) && value.strip.length < min_length.to_i
       label = field['label'] || I18n.t("#{field['key']}.label")
@@ -246,6 +250,10 @@ class CustomWizard::Builder
     end
   end
 
+  def is_text_type(field)
+    ['text', 'textarea'].include? field['type']
+  end
+
   def standardise_boolean(value)
     !!HasCustomFields::Helpers::CUSTOM_FIELD_TRUE.include?(value)
   end