diff --git a/src/rules/declaration-block-no-duplicate-properties/index.js b/src/rules/declaration-block-no-duplicate-properties/index.js
index 1f15f341e2..45793a2c1c 100644
--- a/src/rules/declaration-block-no-duplicate-properties/index.js
+++ b/src/rules/declaration-block-no-duplicate-properties/index.js
@@ -1,7 +1,7 @@
 import {
-  isStandardDeclaration,
-  optionsHaveIgnored,
   isCustomProperty,
+  isStandardProperty,
+  optionsHaveIgnored,
   report,
   ruleMessages,
   validateOptions,
@@ -44,10 +44,9 @@ export default function (on, options) {
         }
 
         if (child.type !== "decl") { return }
-        if (!isStandardDeclaration(child)) { return }
 
         const { prop } = child
-
+        if (!isStandardProperty(prop)) { return }
         if (isCustomProperty(prop)) { return }
 
         // Ignore the src property as commonly duplicated in at-fontface
diff --git a/src/rules/declaration-block-properties-order/index.js b/src/rules/declaration-block-properties-order/index.js
index 4442e29e74..d5fd04f200 100644
--- a/src/rules/declaration-block-properties-order/index.js
+++ b/src/rules/declaration-block-properties-order/index.js
@@ -1,8 +1,8 @@
 import _ from "lodash"
 import { vendor } from "postcss"
 import {
-  isStandardDeclaration,
   isCustomProperty,
+  isStandardProperty,
   report,
   ruleMessages,
   validateOptions,
@@ -55,11 +55,9 @@ export default function (expectation, options) {
         }
 
         if (child.type !== "decl") { return }
-
-        if (!isStandardDeclaration(child)) { return }
-
+  
         const { prop } = child
-
+        if (!isStandardProperty(prop)) { return }
         if (isCustomProperty(prop)) { return }
 
         let unprefixedPropName = vendor.unprefixed(prop)
diff --git a/src/rules/function-comma-space-after/index.js b/src/rules/function-comma-space-after/index.js
index 7121da14ac..a7f67d5a70 100644
--- a/src/rules/function-comma-space-after/index.js
+++ b/src/rules/function-comma-space-after/index.js
@@ -1,7 +1,6 @@
 import valueParser from "postcss-value-parser"
 import {
   declarationValueIndex,
-  isStandardDeclaration,
   isStandardFunction,
   report,
   ruleMessages,
@@ -44,8 +43,6 @@ export default function (expectation) {
 
 export function functionCommaSpaceChecker({ locationChecker, root, result, checkedRuleName }) {
   root.walkDecls(decl => {
-    if (!isStandardDeclaration(decl)) { return }
-
     valueParser(decl.value).walk(valueNode => {
       if (valueNode.type !== "function") { return }
 
diff --git a/src/rules/function-parentheses-newline-inside/index.js b/src/rules/function-parentheses-newline-inside/index.js
index b40c782aea..9f53599ca3 100644
--- a/src/rules/function-parentheses-newline-inside/index.js
+++ b/src/rules/function-parentheses-newline-inside/index.js
@@ -2,7 +2,6 @@ import valueParser from "postcss-value-parser"
 import {
   declarationValueIndex,
   isSingleLineString,
-  isStandardDeclaration,
   isStandardFunction,
   report,
   ruleMessages,
@@ -33,8 +32,6 @@ export default function (expectation) {
     if (!validOptions) { return }
 
     root.walkDecls(decl => {
-      if (!isStandardDeclaration(decl)) { return }
-
       if (decl.value.indexOf("(") === -1) { return }
 
       valueParser(decl.value).walk(valueNode => {
diff --git a/src/rules/function-parentheses-space-inside/index.js b/src/rules/function-parentheses-space-inside/index.js
index a2eb18e3cb..01e7dbc992 100644
--- a/src/rules/function-parentheses-space-inside/index.js
+++ b/src/rules/function-parentheses-space-inside/index.js
@@ -2,7 +2,6 @@ import valueParser from "postcss-value-parser"
 import {
   declarationValueIndex,
   isSingleLineString,
-  isStandardDeclaration,
   isStandardFunction,
   report,
   ruleMessages,
@@ -36,7 +35,6 @@ export default function (expectation) {
     if (!validOptions) { return }
 
     root.walkDecls(decl => {
-      if (!isStandardDeclaration(decl)) { return }
 
       if (decl.value.indexOf("(") === -1) { return }
 
diff --git a/src/rules/property-blacklist/index.js b/src/rules/property-blacklist/index.js
index 08dae9e55e..4915e41587 100644
--- a/src/rules/property-blacklist/index.js
+++ b/src/rules/property-blacklist/index.js
@@ -1,9 +1,9 @@
 import { vendor } from "postcss"
 import { isString } from "lodash"
 import {
-  isStandardDeclaration,
-  matchesStringOrRegExp,
   isCustomProperty,
+  isStandardProperty,
+  matchesStringOrRegExp,
   report,
   ruleMessages,
   validateOptions,
@@ -25,9 +25,8 @@ export default function (blacklistInput) {
     if (!validOptions) { return }
 
     root.walkDecls(decl => {
-      if (!isStandardDeclaration(decl)) { return }
-
       const { prop } = decl
+      if (!isStandardProperty(prop)) { return }
       if (isCustomProperty(prop)) { return }
       if (!matchesStringOrRegExp(vendor.unprefixed(prop), blacklist)) { return }
 
diff --git a/src/rules/property-case/index.js b/src/rules/property-case/index.js
index 48720bb4f2..28fad74191 100644
--- a/src/rules/property-case/index.js
+++ b/src/rules/property-case/index.js
@@ -1,6 +1,6 @@
 import {
-  isStandardDeclaration,
   isCustomProperty,
+  isStandardProperty,
   report,
   ruleMessages,
   validateOptions,
@@ -24,9 +24,8 @@ export default function (expectation) {
     if (!validOptions) { return }
 
     root.walkDecls(decl => {
-      if (!isStandardDeclaration(decl)) { return }
-
       const { prop } = decl
+      if (!isStandardProperty(prop)) { return }
       if (isCustomProperty(prop)) { return }
 
       const expectedProp = expectation === "lower" ? prop.toLowerCase() : prop.toUpperCase()
diff --git a/src/rules/property-whitelist/index.js b/src/rules/property-whitelist/index.js
index 47d19e1e2d..b5385a9d97 100644
--- a/src/rules/property-whitelist/index.js
+++ b/src/rules/property-whitelist/index.js
@@ -1,12 +1,12 @@
 import { vendor } from "postcss"
 import { isString } from "lodash"
 import {
-  isStandardDeclaration,
   isCustomProperty,
+  isStandardProperty,
+  matchesStringOrRegExp,
   report,
   ruleMessages,
   validateOptions,
-  matchesStringOrRegExp,
 } from "../../utils"
 
 export const ruleName = "property-whitelist"
@@ -26,11 +26,9 @@ export default function (whitelistInput) {
 
     root.walkDecls(decl => {
 
-      if (!isStandardDeclaration(decl)) { return }
-
       const { prop } = decl
+      if (!isStandardProperty(prop)) { return }
       if (isCustomProperty(prop)) { return }
-
       if (matchesStringOrRegExp(vendor.unprefixed(prop), whitelist)) { return }
 
       report({
diff --git a/src/rules/root-no-standard-properties/index.js b/src/rules/root-no-standard-properties/index.js
index 2720500eda..81d919fdeb 100644
--- a/src/rules/root-no-standard-properties/index.js
+++ b/src/rules/root-no-standard-properties/index.js
@@ -1,6 +1,6 @@
 import selectorParser from "postcss-selector-parser"
 import {
-  isStandardDeclaration,
+  isStandardProperty,
   isCustomProperty,
   report,
   ruleMessages,
@@ -26,10 +26,9 @@ export default function (actual) {
         if (ignoreRule(selectorAST)) { return }
 
         rule.walkDecls(function (decl) {
-          if (!isStandardDeclaration(decl)) { return }
 
           const { prop } = decl
-
+          if (!isStandardProperty(prop)) { return }
           if (isCustomProperty(prop)) { return }
 
           report({
diff --git a/src/rules/shorthand-property-no-redundant-values/index.js b/src/rules/shorthand-property-no-redundant-values/index.js
index c920f31eb1..d1f0a86a9c 100644
--- a/src/rules/shorthand-property-no-redundant-values/index.js
+++ b/src/rules/shorthand-property-no-redundant-values/index.js
@@ -1,8 +1,6 @@
 import valueParser from "postcss-value-parser"
 import { vendor } from "postcss"
 import {
-  isStandardDeclaration,
-  isCustomProperty,
   report,
   ruleMessages,
   validateOptions,
@@ -65,12 +63,8 @@ export default function (actual) {
 
     root.walkDecls(decl => {
 
-      if (!isStandardDeclaration(decl)) { return }
-
       const { prop, value } = decl
 
-      if (isCustomProperty(prop)) { return }
-
       // ignore not shorthandable properties, and math operations
       if (
         isIgnoredCharacters(value) ||
diff --git a/src/utils/__tests__/isStandardDeclaration-test.js b/src/utils/__tests__/isStandardDeclaration-test.js
index 4c47c5fe10..9d4130c998 100644
--- a/src/utils/__tests__/isStandardDeclaration-test.js
+++ b/src/utils/__tests__/isStandardDeclaration-test.js
@@ -1,11 +1,10 @@
 import isStandardDeclaration from "../isStandardDeclaration"
-import less from "postcss-less"
 import postcss from "postcss"
 import test from "tape"
 
 test("isStandardDeclaration", t => {
 
-  t.plan(8)
+  t.plan(7)
 
   rules("a { a: b }", decl => {
     t.ok(isStandardDeclaration(decl), "standard prop and value")
@@ -29,10 +28,6 @@ test("isStandardDeclaration", t => {
   rules("$map: (value, value2)", decl => {
     t.notOk(isStandardDeclaration(decl), "scss map")
   })
-
-  lessRules("a { @var: b }", decl => {
-    t.notOk(isStandardDeclaration(decl), "less var")
-  })
 })
 
 function rules(css, cb) {
@@ -40,9 +35,3 @@ function rules(css, cb) {
     result.root.walkDecls(cb)
   })
 }
-
-function lessRules(css, cb) {
-  postcss().process(css, { syntax: less }).then(result => {
-    result.root.walkDecls(cb)
-  })
-}
diff --git a/src/utils/__tests__/isStandardProperty-test.js b/src/utils/__tests__/isStandardProperty-test.js
new file mode 100644
index 0000000000..ae4310957d
--- /dev/null
+++ b/src/utils/__tests__/isStandardProperty-test.js
@@ -0,0 +1,12 @@
+import test from "tape"
+import isStandardProperty from "../isStandardProperty"
+
+test("isStandardProperty", t => {
+  t.ok(isStandardProperty("top"), "single word")
+  t.ok(isStandardProperty("--custom-property"), "custom property")
+  t.ok(isStandardProperty("border-top-left-radius"), "hyphenated words")
+  t.ok(isStandardProperty("-webkit-appearance"), "vendor prefix")
+  t.notOk(isStandardProperty("$sass-variable"), "sass variable")
+  t.notOk(isStandardProperty("@less-variable"), "less variable")
+  t.end()
+})
diff --git a/src/utils/index.js b/src/utils/index.js
index c4cf9f49b6..09545c8304 100644
--- a/src/utils/index.js
+++ b/src/utils/index.js
@@ -17,6 +17,7 @@ export { default as isLowerSpecificity } from "./isLowerSpecificity"
 export { default as isSingleLineString } from "./isSingleLineString"
 export { default as isStandardDeclaration } from "./isStandardDeclaration"
 export { default as isStandardFunction } from "./isStandardFunction"
+export { default as isStandardProperty } from "./isStandardProperty"
 export { default as isStandardRule } from "./isStandardRule"
 export { default as isStandardSelector } from "./isStandardSelector"
 export { default as isStandardTypeSelector } from "./isStandardTypeSelector"
diff --git a/src/utils/isStandardDeclaration.js b/src/utils/isStandardDeclaration.js
index ee39c0e514..4170c10230 100644
--- a/src/utils/isStandardDeclaration.js
+++ b/src/utils/isStandardDeclaration.js
@@ -5,13 +5,9 @@
  * @return {boolean} If `true`, the declaration is standard
  */
 export default function (decl) {
-  const { prop } = decl
 
-  // SCSS var (e.g. $var: x), list (e.g. $list: (x)) or map (e.g. $map: (key:value))
-  if (prop[0] === "$") { return false }
-
-  // Less var (e.g. @var: x)
-  if (prop[0] === "@") { return false }
+  // Declarations belong in a declaration block
+  if (decl.parent.type === "root") { return false }
 
   return true
 }
diff --git a/src/utils/isStandardProperty.js b/src/utils/isStandardProperty.js
new file mode 100644
index 0000000000..03972ceb44
--- /dev/null
+++ b/src/utils/isStandardProperty.js
@@ -0,0 +1,16 @@
+/**
+ * Check whether a property is standard
+ *
+ * @param {string} property
+ * @return {boolean} If `true`, the property is standard
+ */
+export default function (property) {
+
+  // SCSS var (e.g. $var: x), list (e.g. $list: (x)) or map (e.g. $map: (key:value))
+  if (property[0] === "$") { return false }
+
+  // Less var (e.g. @var: x)
+  if (property[0] === "@") { return false }
+
+  return true
+}