How Scoring Works
Discover the transparent methodology behind how we evaluate water quality, filters, and safety across all products in our database.
Overview
We all need water, but not all water is the same. Whether it's bottled, straight from the tap, or filtered, understanding the cleanliness and health of water is vital for taking care of our health and supporting longevity.
Every water has its own unique characteristics and we've created a scoring system to help you understand the quality of the water you drink. Please note our scoring system is subject to change in light of new scientific evidence and research.
Open Source Commitment
We choose to open-source our scoring system to allow for transparency and to encourage feedback and improvement from the community.
Everything is scored out of 100, and we penalize each item depending on several key factors:
Evaluation Factors
- Contaminants
- Lab verification
- Source quality
- PFAS testing
- Packaging type
- pH levels
Contaminant Penalties
- • Severity score (1-5) × amount over guideline
- • Max penalty per contaminant: 60 points
- • No lab report: 25 point penalty
Source Penalties
- • Municipal water: -15 points
- • Rain water: -10 points
- • Spring water: +10 points (bonus)
- • Aquifer water: +10 points (bonus)
Important Note
Tap water scores are not directly comparable to bottled water scores. While tap water might receive a score of 30 and bottled water a score of 25, this does not necessarily mean the tap water is better.
Base Scoring
Starts at 100 points
- • 5 points per contaminant
- • Amount above guidelines
- • Max 45 points per contaminant
Normalization
Ensures meaningful scores
- • Scores between 1-100
- • Ratio-based calculation
- • Rounded to whole numbers
Penalty Calculation
Fair assessment method
- • Total penalty ÷ 2
- • Maintains balance
- • Comparable scoring
We analyze testing reports to determine effectiveness in removing contaminants. Our scoring considers both removal percentage and contaminant importance.
High Priority Contaminants
Medium Priority Contaminants
Harmful Ingredients
Up to 85 points penalty
- • Severity score (1-5 scale)
- • Amount vs. guidelines
- • Max 5x severity per ingredient
Lab Verification
10 points penalty if missing
- • Ensures transparency
- • Accountability in testing
- • Verified results preferred
Packaging Impact
Up to 5 points penalty
- • Glass: 0 points (best)
- • Plastic: 5 points
- • Aluminum: 5 points
Enhanced Food Scoring
Food items receive doubled severity scores for harmful ingredients to account for food-specific health guidelines and enhanced safety requirements.
Scoring Components
Harmful Ingredients (0-85 pts)
Doubled severity for food safety
Lab Verification (0-10 pts)
Ingredient verification required
Packaging (0-5 pts)
Food-safe packaging assessment
Special Considerations
- Beneficial ingredients tracked but don't affect score
- Food-specific health guidelines applied
- Enhanced safety requirements for consumables
Open Source Rating System
Our rating system is transparent, based on the latest scientific research, and continuously updated. We welcome community feedback to improve our methodology.