diff --git a/.github/workflows/build-dist-test.ps1 b/.github/workflows/build-dist-test.ps1
index db6c2b8cb3..46f42cd740 100644
--- a/.github/workflows/build-dist-test.ps1
+++ b/.github/workflows/build-dist-test.ps1
@@ -57,6 +57,7 @@ if ($LASTEXITCODE -ne 0) {
 }
 # Add a few extras we have to pull in from conda-forge.
 # See Also: mlos-windows.yml
+conda install -y -v -n mlos-dist-test swig libpq
 # FIXME: conda on Windows doesn't appear to respect ">=0.9.0" as a version constraint despite various quoting tweaks.
 conda install -y -v -n mlos-dist-test -c conda-forge 'pyrfr=0.9'
 if ($LASTEXITCODE -ne 0) {
diff --git a/Makefile b/Makefile
index 679a22b24b..2386f80128 100644
--- a/Makefile
+++ b/Makefile
@@ -248,6 +248,8 @@ build/dist-test-env.$(PYTHON_VERSION).build-stamp: mlos_core/dist/tmp/mlos_core-
 	# Create a clean test environment for checking the wheel files.
 	$(MAKE) dist-test-env-clean
 	conda create -y ${CONDA_INFO_LEVEL} -n mlos-dist-test-$(PYTHON_VERSION) python=$(PYTHON_VERS_REQ)
+	# Install some additional dependencies necessary for clean building some of the wheels.
+	conda install -y ${CONDA_INFO_LEVEL} -n mlos-dist-test-$(PYTHON_VERSION) swig libpq
 	# Test a clean install of the mlos_core wheel.
 	conda run -n mlos-dist-test-$(PYTHON_VERSION) pip install "mlos_core/dist/tmp/mlos_core-latest-py3-none-any.whl[full-tests]"
 	# Test a clean install of the mlos_bench wheel.
diff --git a/conda-envs/mlos-3.10.yml b/conda-envs/mlos-3.10.yml
index 7c28c48f0e..0f47acae93 100644
--- a/conda-envs/mlos-3.10.yml
+++ b/conda-envs/mlos-3.10.yml
@@ -16,6 +16,8 @@ dependencies:
   - nb_conda_kernels
   - matplotlib
   - seaborn
+  - swig
+  - libpq
   - python=3.10
   # See comments in mlos.yml.
   #- gcc_linux-64
diff --git a/conda-envs/mlos-3.11.yml b/conda-envs/mlos-3.11.yml
index 505e3c1ce1..65aaa87deb 100644
--- a/conda-envs/mlos-3.11.yml
+++ b/conda-envs/mlos-3.11.yml
@@ -17,6 +17,7 @@ dependencies:
   - matplotlib
   - seaborn
   - swig
+  - libpq
   - python=3.11
   # See comments in mlos.yml.
   #- gcc_linux-64
diff --git a/conda-envs/mlos-3.8.yml b/conda-envs/mlos-3.8.yml
index 3821b3e503..3720eaf6f7 100644
--- a/conda-envs/mlos-3.8.yml
+++ b/conda-envs/mlos-3.8.yml
@@ -16,6 +16,8 @@ dependencies:
   - nb_conda_kernels
   - matplotlib
   - seaborn
+  - swig
+  - libpq
   - python=3.8
   # See comments in mlos.yml.
   #- gcc_linux-64
diff --git a/conda-envs/mlos-3.9.yml b/conda-envs/mlos-3.9.yml
index 8f26d91040..0ec7d02ca2 100644
--- a/conda-envs/mlos-3.9.yml
+++ b/conda-envs/mlos-3.9.yml
@@ -16,6 +16,8 @@ dependencies:
   - nb_conda_kernels
   - matplotlib
   - seaborn
+  - swig
+  - libpq
   - python=3.9
   # See comments in mlos.yml.
   #- gcc_linux-64
diff --git a/conda-envs/mlos-windows.yml b/conda-envs/mlos-windows.yml
index 18d0e7f612..d56c8841a6 100644
--- a/conda-envs/mlos-windows.yml
+++ b/conda-envs/mlos-windows.yml
@@ -20,6 +20,7 @@ dependencies:
   - matplotlib
   - seaborn
   - swig
+  - libpq
   - python
   # Install an SMAC requirement pre-compiled from conda-forge.
   # This also requires a more recent vs2015_runtime from conda-forge.
diff --git a/conda-envs/mlos.yml b/conda-envs/mlos.yml
index f9551bd3a8..bb0b39e55e 100644
--- a/conda-envs/mlos.yml
+++ b/conda-envs/mlos.yml
@@ -17,6 +17,7 @@ dependencies:
   - matplotlib
   - seaborn
   - swig
+  - libpq
   - python
   - pip:
     - autopep8>=1.7.0