diff --git a/packages/react-scripts/config/webpack.config.js b/packages/react-scripts/config/webpack.config.js
index 1e304d76046..9781875bd30 100644
--- a/packages/react-scripts/config/webpack.config.js
+++ b/packages/react-scripts/config/webpack.config.js
@@ -108,7 +108,7 @@ module.exports = function(webpackEnv) {
               stage: 3,
             }),
           ],
-          sourceMap: isEnvProduction && shouldUseSourceMap,
+          sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
         },
       },
     ].filter(Boolean);
@@ -116,7 +116,7 @@ module.exports = function(webpackEnv) {
       loaders.push({
         loader: require.resolve(preProcessor),
         options: {
-          sourceMap: isEnvProduction && shouldUseSourceMap,
+          sourceMap: isEnvProduction ? shouldUseSourceMap : isEnvDevelopment,
         },
       });
     }
@@ -441,7 +441,9 @@ module.exports = function(webpackEnv) {
               exclude: cssModuleRegex,
               use: getStyleLoaders({
                 importLoaders: 1,
-                sourceMap: isEnvProduction && shouldUseSourceMap,
+                sourceMap: isEnvProduction
+                  ? shouldUseSourceMap
+                  : isEnvDevelopment,
               }),
               // Don't consider CSS imports dead code even if the
               // containing package claims to have no side effects.
@@ -455,7 +457,9 @@ module.exports = function(webpackEnv) {
               test: cssModuleRegex,
               use: getStyleLoaders({
                 importLoaders: 1,
-                sourceMap: isEnvProduction && shouldUseSourceMap,
+                sourceMap: isEnvProduction
+                  ? shouldUseSourceMap
+                  : isEnvDevelopment,
                 modules: true,
                 getLocalIdent: getCSSModuleLocalIdent,
               }),
@@ -469,7 +473,9 @@ module.exports = function(webpackEnv) {
               use: getStyleLoaders(
                 {
                   importLoaders: 2,
-                  sourceMap: isEnvProduction && shouldUseSourceMap,
+                  sourceMap: isEnvProduction
+                    ? shouldUseSourceMap
+                    : isEnvDevelopment,
                 },
                 'sass-loader'
               ),
@@ -486,7 +492,9 @@ module.exports = function(webpackEnv) {
               use: getStyleLoaders(
                 {
                   importLoaders: 2,
-                  sourceMap: isEnvProduction && shouldUseSourceMap,
+                  sourceMap: isEnvProduction
+                    ? shouldUseSourceMap
+                    : isEnvDevelopment,
                   modules: true,
                   getLocalIdent: getCSSModuleLocalIdent,
                 },