Place the butter in a large heavy-bottomed pot over medium heat. Once melted, add the carrots, celery, and onion, then cook until the vegetables are soft but not browned, about 5 to 7 minutes.
Add the water and potatoes, increase the heat to high, and bring the mixture to a boil with the lid slightly ajar. Once boiling, reduce the heat to medium low and simmer for about 15 minutes, or until the potatoes can easily be pierced with a fork.
Add the salmon, haddock, evaporated milk, salt, and pepper. Increase the heat to medium and simmer for 5 to 8 minutes, or until the fish is cooked through. Taste the chowder, adjust the seasoning if needed, then serve hot with crusty bread or crackers.
Notes
For detailed ingredient notes, substitution tips, variations, and step-by-step photos, scroll through the full recipe post.
Use a digital kitchen scale for precise measurements and an oven thermometer to confirm your oven is heating correctly.
To switch to gram measurements, click "Metric grams" in the ingredients section of the recipe card.
If you like a thicker chowder, stir together 1 tablespoon of cornstarch or all-purpose flour with 2 tablespoons of cold water to make a slurry, then slowly stir it into the simmering chowder and cook for 2 to 3 minutes until thickened.
Storage
Store leftover chowder in an airtight container in the refrigerator for up to 3 days. Reheat gently over low heat on the stovetop, stirring occasionally, until warmed through. Avoid boiling when reheating to keep the broth smooth.