diff --git a/httpx/_models.py b/httpx/_models.py
index 31ff9363a7..bf965a141d 100644
--- a/httpx/_models.py
+++ b/httpx/_models.py
@@ -1,4 +1,3 @@
-import codecs
 import datetime
 import email.message
 import json as jsonlib
@@ -758,40 +757,8 @@ def raise_for_status(self) -> "Response":
         message = message.format(self, error_type=error_type)
         raise HTTPStatusError(message, request=request, response=self)
 
-    def _guess_content_json_utf(self) -> typing.Optional[str]:
-        # JSON always starts with two ASCII characters, so detection is as
-        # easy as counting the nulls and from their location and count
-        # determine the encoding. Also detect a BOM, if present.
-        sample = self.content[:4]
-        if sample in (codecs.BOM_UTF32_LE, codecs.BOM_UTF32_BE):
-            return "utf-32"  # BOM included
-        if sample[:3] == codecs.BOM_UTF8:
-            return "utf-8-sig"  # BOM included, MS style (discouraged)
-        if sample[:2] in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE):
-            return "utf-16"  # BOM included
-        nullcount = sample.count(b"\0")
-        if nullcount == 0:
-            return "utf-8"
-        if nullcount == 2:
-            if sample[::2] == b"\0\0":  # 1st and 3rd are null
-                return "utf-16-be"
-            if sample[1::2] == b"\0\0":  # 2nd and 4th are null
-                return "utf-16-le"
-            # Did not detect 2 valid UTF-16 ascii-range characters
-        if nullcount == 3:
-            if sample[:3] == b"\0\0\0":
-                return "utf-32-be"
-            if sample[1:] == b"\0\0\0":
-                return "utf-32-le"
-            # Did not detect a valid UTF-32 ascii-range character
-        return None
-
     def json(self, **kwargs: typing.Any) -> typing.Any:
-        if self.charset_encoding is None and self.content and len(self.content) > 3:
-            encoding = self._guess_content_json_utf()
-            if encoding is not None:
-                return jsonlib.loads(self.content.decode(encoding), **kwargs)
-        return jsonlib.loads(self.text, **kwargs)
+        return jsonlib.loads(self.content, **kwargs)
 
     @property
     def cookies(self) -> "Cookies":
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e9ac176f8f..b9d515c89d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,3 +1,4 @@
+import json
 import logging
 import os
 import random
@@ -23,14 +24,16 @@
     ),
 )
 def test_encoded(encoding):
-    data = "{}".encode(encoding)
-    response = httpx.Response(200, content=data)
-    assert response._guess_content_json_utf() == encoding
+    content = '{"abc": 123}'.encode(encoding)
+    response = httpx.Response(200, content=content)
+    assert response.json() == {"abc": 123}
 
 
 def test_bad_utf_like_encoding():
-    response = httpx.Response(200, content=b"\x00\x00\x00\x00")
-    assert response._guess_content_json_utf() is None
+    content = b"\x00\x00\x00\x00"
+    response = httpx.Response(200, content=content)
+    with pytest.raises(json.decoder.JSONDecodeError):
+        response.json()
 
 
 @pytest.mark.parametrize(
@@ -43,9 +46,9 @@ def test_bad_utf_like_encoding():
     ),
 )
 def test_guess_by_bom(encoding, expected):
-    data = "\ufeff{}".encode(encoding)
-    response = httpx.Response(200, content=data)
-    assert response._guess_content_json_utf() == expected
+    content = '\ufeff{"abc": 123}'.encode(encoding)
+    response = httpx.Response(200, content=content)
+    assert response.json() == {"abc": 123}
 
 
 @pytest.mark.parametrize(