diff --git a/etrago/tools/constraints.py b/etrago/tools/constraints.py
index 1a2b5a71..17a7716c 100755
--- a/etrago/tools/constraints.py
+++ b/etrago/tools/constraints.py
@@ -21,9 +21,9 @@
 """
 Constraints.py includes additional constraints for eTraGo-optimizations
 """
+import os
 import logging
 
-from egoio.tools import db
 from pyomo.environ import Constraint
 from pypsa.descriptors import expand_series
 from pypsa.linopt import define_constraints, define_variables, get_var, linexpr
@@ -32,6 +32,9 @@
 import pandas as pd
 import pyomo.environ as po
 
+if "READTHEDOCS" not in os.environ:
+    from egoio.tools import db
+
 logger = logging.getLogger(__name__)
 
 __copyright__ = (
diff --git a/etrago/tools/network.py b/etrago/tools/network.py
index 97ffbfe7..3a1e2c89 100644
--- a/etrago/tools/network.py
+++ b/etrago/tools/network.py
@@ -22,13 +22,16 @@
 Define class Etrago
 """
 
+import os
 import logging
 
-from egoio.tools import db
 from pypsa.components import Network
 from sqlalchemy.orm import sessionmaker
 import pandas as pd
 
+if "READTHEDOCS" not in os.environ:
+    from egoio.tools import db
+
 from etrago import __version__
 from etrago.cluster.disaggregation import run_disaggregation
 from etrago.cluster.electrical import ehv_clustering, run_spatial_clustering
diff --git a/etrago/tools/utilities.py b/etrago/tools/utilities.py
index 47ac8916..cf52b576 100755
--- a/etrago/tools/utilities.py
+++ b/etrago/tools/utilities.py
@@ -29,7 +29,6 @@
 import math
 import os
 
-from egoio.tools import db
 from pyomo.environ import Constraint, PositiveReals, Var
 from shapely.geometry import Point
 import geopandas as gpd
@@ -38,6 +37,9 @@
 import pypsa
 import sqlalchemy.exc
 
+if "READTHEDOCS" not in os.environ:
+    from egoio.tools import db
+
 logger = logging.getLogger(__name__)