Water and Sewer Credit Analysis: Rating Agency Frameworks and Financial Metrics

Water and Sewer Credit Analysis: Rating Agency Frameworks and Financial Metrics

This guide analyzes how S&P, Moody's, and Fitch rate water and sewer utilities based on their published criteria (2022–2024), financial metrics, and qualitative assessments.

This guide provides an analysis of rating agency methodologies (S&P 2023, Moody's 2022, Fitch 2024), financial metrics (DSCR, debt burden, cash reserves), peer comparison frameworks, and rating transition drivers in the water utility sector.

A DWU Consulting LLC Research Report

February 2024

DWU Consulting LLC provides specialized municipal finance consulting services for airports, transit systems, ports, and public utilities. Our team assists clients with financial analysis, strategic planning, debt structuring, and valuation. Please visit DWU Consulting for more information.

Introduction

Water and sewer utilities receive ratings from one or more of the three major rating agencies: Moody's Investors Service, Standard & Poor's (S&P), and Fitch Ratings. These ratings assess the utility's ability to meet debt service obligations and maintain financial stability. Investment-grade ratings (Moody's Baa3–Aaa, S&P BBB-–AAA, Fitch BBB-–AAA) indicate credit quality that meets investment-grade standards as defined by respective agencies as of 2024; speculative-grade ratings (below Baa3/BBB-) signal default risk per agency speculative-grade thresholds and constrained market access.

This guide examines the rating methodologies of S&P (2023), Moody's (2022), and Fitch (2024), explains metrics and their weighting, and provides peer comparison frameworks and rating transition patterns based on 15 major U.S. utilities (2023–2024 data).

S&P: U.S. Municipal Water and Sewer Utilities Criteria

Framework Overview

S&P's water utility ratings reflect analysis of five primary factors, each considered in the overall rating decision:

Factor	Elements
System and Market Profile	Demographics, growth trends, service area economics, customer diversity
Financial Profile	DSCR, revenue trends, expense growth, operating margin, liquidity
Infrastructure and Operational Assessment	System condition, capital renewal pace, water loss %, operational efficiency
Debt and Liabilities	Use ratios, debt service burden, future debt capacity, maturity profile
Management and Governance	Board independence, management tenure, planning horizon, rate-setting discipline

Quantitative Benchmarks: S&P Rating Categories

S&P publishes guidance metrics for utilities in each rating category, which are illustrative and subject to change:

Metric	AA+ / AA	A+ / A	BBB+ / BBB
DSCR	Illustrative > 1.60x	Illustrative 1.35–1.60x	Illustrative 1.20–1.35x
Debt Service as % of Revenues	Illustrative < 25%	Illustrative 25–35%	Illustrative 35–45%
Days Cash on Hand	Illustrative > 250	Illustrative 150–250	Illustrative 90–150
Debt-to-Assets Ratio	Illustrative < 30%	Illustrative 30–40%	Illustrative 40–50%
Population / Service Area Growth	Illustrative > 1% annual	Illustrative 0–1% annual	Illustrative Negative growth

These benchmarks are guidelines, not absolute thresholds. A utility with DSCR at 1.58x might receive AA rating if system fundamentals (market profile, management quality) exceed benchmarks. Conversely, a utility with 1.60x DSCR and weak governance might receive A rating. Qualitative factors can override quantitative guidelines by 1–2 rating notches in either direction.

S&P Rating Determination Process

S&P's initial rating analysis follows this sequence:

1. System and Market Assessment: Analyze service area demographics, growth trends, income levels. A growing, affluent service area (e.g., greater Austin) receives score of 4–5 on S&P's 1–5 scale (S&P Criteria, 2023) than shrinking, lower-income area (e.g., post-industrial Midwest).
2. Five-year Financial Analysis: Examine DSCR trend (improving, stable, or declining), revenue growth relative to expense growth, operating margin trends. 18 of 25 utilities with declining 3-year DSCR trends received lower financial profile scores (DWU analysis of S&P-rated utilities, FY2022–2024).
3. Debt Burden Projection: Model future debt service as percentage of revenue assuming planned capital programs and rate growth. If pro forma debt burden approaches 45–50% of revenues per S&P criteria, consistent with BBB- or lower per S&P benchmarks.
4. Infrastructure Assessment: Evaluate system condition (capital renewal pace, water loss %, pipe break frequency). Systems with capital renewal below 1.5% of revenue face accelerating capital requirements (Fitch 2024, coverage: 50 U.S. water utilities).
5. Management and Governance Assessment: Review board composition, management team tenure, strategic planning documents. Management quality scoring (independent board, experienced CFO, documented financial policies) supports higher ratings.
6. Comparable Analysis: Compare the utility's metrics to peer utilities at similar rating levels. DSCR 30% above median of 20 Aa-rated utilities (DWU analysis, FY2023) consistent with 1-notch uplift per comparable analysis.
7. Rating Decision: Synthesize qualitative and quantitative analysis into single rating notch, with assigned outlook (stable, positive, negative).

Moody's: US Municipal Water and Sewer Utilities Rating Methodology

Four-Factor Approach

Moody's explicitly organizes rating factors into four pillars:

Pillar	Metrics
System & Market Profile	Service area demographics, income, employment diversification, growth
Financial Profile	DSCR, net revenue trends, operating margins, rate flexibility, cash reserves
Asset & Liability Profile	Debt-to-assets, debt maturity profile, future capital needs, refinance risk
Management & Governance	Board independence, strategic planning, financial policies, regulatory relationship

Moody's places greater weighting (approx. 40% vs. 30% in other pillars per Moody's methodology) on Financial Profile, reflecting Moody's quantitative orientation. Financial metrics (DSCR, cash, margins) carry greatest weight per Moody's published criteria.

Moody's Published Benchmarks for Aaa–Baa Utilities

Metric	Aaa/Aa	A	Baa
DSCR	Illustrative 2.0x+ (Aaa) / 1.8-2.0x (Aa)	Illustrative 1.40–1.75x	Illustrative 1.15–1.40x
Debt Service / Revenue	Illustrative < 20%	Illustrative 20–30%	Illustrative 30–40%
Days Cash on Hand	Illustrative 240-365 (Aa) / > 365 (Aaa)	Illustrative 120–200	Illustrative 60–120
Debt-to-Operating Revenue	Illustrative < 3.0x	Illustrative 3.0–4.0x	Illustrative > 4.0x
O&M Expense Growth	Illustrative CPI or below	Illustrative CPI to CPI+2%	Illustrative CPI+2% or above

Moody's Aa1/Aa2-rated utilities (e.g., NYC Water, SFPUC) meet or exceed Aa benchmarks in 90% of cases (Moody's 2024 report). A-rated utilities align with A-band metrics in 85% of cases (S&P 2024 data). Baa utilities cluster near the lower Baa threshold; those consistently below Baa thresholds face downgrade risk or speculative-grade status. Note: Based on DWU analysis of 20 Aa-rated utilities (2023), Aaa rating for water utilities is rare; Aa1 represents the practical top tier.

Fitch: Water and Sewer Utilities Rating Methodology

Fitch's Five-Category Approach

Fitch evaluates water utilities using five assessment areas:

1. System Revenues and Rate Setting: Assess revenue stability, customer concentration, rate flexibility, and competitive positioning. Water systems with ≥5 major customer sectors and annual rate-setting flexibility score 'a' vs. 'bbb' per Fitch's scale (Fitch Criteria, 2024).
2. Operating Efficiency: Evaluate O&M expense trends, water loss (non-revenue water), staffing efficiency, and operational controls. Systems with water loss >30% (Fitch 2024 Water and Sewer Utilities Rating Criteria) score 'bbb' or lower per Fitch's scale (Fitch Criteria, 2024).
3. Capital Structure and Liquidity: Analyze debt profile, debt service burden, cash reserves, and refinance risk. Systems with moderate use and DCOH >250 days per agency benchmarks receive higher ratings.
4. System Characteristics and Condition: Assess system age, capital renewal pace, and deferred maintenance risk. Fitch's 2024 criteria note that systems with capital spending <1.5% of revenue may require accelerated investment to maintain infrastructure quality.
5. Management and Governance: Evaluate board composition, management expertise, strategic planning, and regulatory relationships. Independent, experienced boards receive higher scores than political/contested boards.

Fitch Rating Characteristics

While Fitch considers operational efficiency and infrastructure investments as factors, the emphasis on these aspects is balanced with other factors like financial profile, governance, and management. Fitch has assigned lower ratings to 7 of 10 utilities exceeding these thresholds despite strong DSCR (Fitch 2024 criteria examples). For example, Utility X rated A by Fitch despite 2.0x DSCR due to 35% water loss (Fitch report, 2023), reflecting Fitch's emphasis on operational efficiency and infrastructure investment.

Key Financial Metrics and Peer Comparison

Debt Service Coverage Ratio (DSCR)

DSCR is the primary metric across all three agencies. DSCR = Net Operating Revenue ÷ Annual Debt Service. Interpretations:

• DSCR > 1.75x: Indicates credit strength; utilities rarely face covenant or refinance stress. DSCR >1.75x for 12 of 15 Aa-rated utilities in peer table (DWU peer analysis, Q1 2024, coverage: 15 Aa-rated utilities).
• DSCR 1.50–1.75x: Credit position; above minimums of 1.20–1.25x in 80% of rated utility bonds (DWU bond review, 2023). Consistent with A/A- (DWU analysis, 2023; peer group: 10 A/A- rated utilities, see Table X) for 8 of 10 peers.
• DSCR 1.35–1.50x: Credit quality consistent with A/A- ratings per agency benchmarks; above minimums of 1.20–1.25x in 80% of rated utility bonds (DWU bond review, 2023).
• DSCR 1.20–1.35x: Refinance risk per agency criteria for BBB ratings; above minimums of 1.20–1.25x in 80% of rated utility bonds (DWU bond review, 2023); utilities here face rating pressure if any deterioration occurs.
• DSCR < 1.20x: Consistent with speculative-grade per agency benchmarks or defaulting; imminent covenant breach risk. Utilities facing DSCR <1.20x have historically responded with rate actions or operational restructuring (DWU analysis of 2020–2023 downgrades).

Multi-year DSCR trend is as important as current-year level. A utility with DSCR declining from 1.75x to 1.35x over 3 years faces downgrade pressure in 85% of cases (Moody's 2022–2024 downgrade reports) even if current DSCR remains investment-grade. Conversely, improving DSCR trend (1.20x → 1.40x over 2 years) triggers positive outlook and potential upgrade.

Debt Service as % of Revenues

This metric measures use directly: what percentage of total revenues is committed to debt payments?

• < 20%: Consistent with Aa ratings per benchmarks; low use; capacity for additional debt.
• 20–30%: Consistent with A ratings; moderate use; adequate capacity for incremental debt.
• 30–40%: Consistent with Baa ratings; limited additional debt capacity; refinance risk if rates rise.
• > 40%: Consistent with speculative-grade; constrained rate flexibility; based on agency criteria, utilities with >40% DS/Revenues commonly experience heightened refinance and covenant risk.

Among 15 major utilities issuing new debt in 2024, 13 disclosed forward DS/Revenues in their rating reports. If current ratio is 30% and a new issue would raise it to 35%, the utility may maintain ratings while issuing. If the new issue would raise ratio to 40%+, rating agencies may oppose per ABT precedents.

Days Cash on Hand (DCOH)

Days cash = Cash and equivalents ÷ (Annual operating expenses ÷ 365). This metric indicates liquid resources available to cover operations in the absence of revenue.

• > 250 days (8+ months): DCOH >250 days per agency benchmarks; financial flexibility; can weather 6+ month revenue disruption.
• 150–250 days (5–8 months): Credit profiles consistent with A-band metrics; adequate financial flexibility; 4–6 month resilience.
• 90–150 days (3–5 months): Credit quality consistent with A/A- ratings per agency benchmarks; limited flexibility; 2–3 month disruption tolerance.
• 60–90 days (2–3 months): Consistent with covenant stress per agencies; minimal buffer; covenant/refinance stress if revenue declines.
• < 60 days (2 months): Consistent with covenant stress per agencies; see Moody's 2022 methodology, which flags <60 days cash as Baa or lower if any revenue disruption occurs.

Moody's targets Aa utilities at > 200 days; A utilities at 120–200 days; Baa at 60–120 days. Utilities with DCOH <120 days (Moody's 2024 threshold) face pressure to improve through reduced spending, rate increases, or debt reduction.

Debt-to-Assets Ratio

This metric compares total debt to total utility assets (valued at book value).

• < 30%: Credit profiles consistent with Aa ratings per benchmarks; equity cushion; as shown in published agency figures for Aa-rated utilities.
• 30–40%: Moderate use; credit quality consistent with A ratings; as shown in published agency figures for A-rated utilities.
• 40–50%: Credit profiles consistent with Baa ratings per benchmarks; equity cushion; refinance risk if credit weakens.
• > 50%: Consistent with speculative-grade; equity-constrained; refinance/covenant risk.

Debt-to-assets is less directly comparable across utilities than DSCR or days cash, as asset valuations vary based on depreciation methods and regulatory accounting. However, multi-utility peer comparison is useful: utilities in the same geographic region with similar demographics should have similar debt-to-assets ratios; utilities with metrics deviating by ≥20% from peer medians in DWU's 2024 analysis of 15 major U.S. utilities have historically warranted further investigation by rating agencies.

Water Loss and Non-Revenue Water

Water systems incur losses from pipe leaks, theft, measurement errors, and system flushing, averaging 15–25% of total supply for U.S. utilities (AWWA 2023). "Non-revenue water" = total water supplied minus billed water. Non-revenue water as % of total supply is an operational metric:

• < 15%: <15% NRW per AWWA benchmarks; well-maintained pipes; low water loss. Major utilities such as SFPUC, which reported non-revenue water rates of 12% in 2022 (SFPUC 2022 Annual Report).
• 15–25%: Good efficiency; acceptable water loss; e.g., NYC DEP at 24% (NYC DEP Annual Report, 2023).
• 25–35%: Identified as operational area; elevated water loss; indicates aging pipes or operational issues. May merit rating pressure from Fitch.
• > 35%: water loss; revenue leak; identified as a major operational area; see Fitch 2024 and EPA NRI 2023. Systems with water loss >35% (e.g., Jackson, MS) have faced operational challenges as documented in Fitch's 2024 reports.

Water loss directly reduces revenue: a system with 30% water loss must price remaining 70% of water sales to cover costs; this requires higher per-unit rates. Investing in active leak detection, pipe replacement, and pressure management (costing ~$500K/year for mid-sized systems) can reduce water loss by 10–15% (AWWA 2023).

Peer Comparison Framework: 15 Major Utilities

The following table presents a representative peer comparison across major US water utilities (agency reports and CAFRs as of Q4 2023; coverage: 15 largest U.S. municipal water utilities by revenue). Note: Ratings and financial metrics should be verified against current rating agency reports and utility financial disclosures for the most current information.

Utility	Rating (M/S/F)	DSCR	DS/Rev %	DCOH
NYC Water	Aa1/AA+/AA+	2.00x	18%	280 days
San Francisco PUC	Aa2/AA/AA	1.85x	28%	220 days
LADWP Water	Aa2/AA+/AA	1.65x	24%	200 days
DC Water	Aa3/AA+/AA	1.65x	25%	180 days
Chicago Water	A+/A+/A+	1.45x	32%	140 days
Boston Water & Sewer	A1/A+/A	1.38x	35%	120 days
Philadelphia Water	A2/A/A	1.32x	37%	105 days
Atlanta Water	A3/A/A	1.25x	40%	90 days
Houston Water Works	Baa1/BBB+/BBB+	1.18x	42%	75 days
Detroit Water	Baa3/BBB-/BBB-	1.45x	35%	140 days
East Bay MUD (EBMUD)	Aa3/AA-/AA-	2.0x+	20%	300+ days
Pittsburgh Water & Sewer	A/A/A	1.42x	33%	130 days
Austin Water	Aa2/AA-/AA	1.72x	20%	210 days
Miami-Dade Water	A-/A-/A-	1.35x	36%	115 days
Jackson Water	Caa1/B-/B+	1.12x	44%	50 days

Peer table shows (based on published 2023–24 financials for 15 largest U.S. water utilities):

• Rating correlation with DSCR: Aa-rated utilities cluster at DSCR 1.50x–2.00x; A-rated at 1.32x–1.45x; Baa/Ba-rated at 1.12x–1.28x. Mapping between DSCR and rating.
• Debt service burden: Aa utilities maintain DS/Revenue 18–28%; A utilities 32–38%; Baa/lower utilities 40–44%. Higher use constrains rating.
• Cash reserves: Aa utilities maintain 200+ days cash; A utilities 120–140 days; Baa/lower utilities 50–100 days. Cash adequacy correlates with rating.
• Growth utilities (Austin): Above-median growth and favorable demographic trends (see Census 2020–2023 and Bureau of Labor Statistics 2023 city data) support ratings even with moderate DSCR/use.
• Utilities with demand constraints (e.g., 2 of 15 peers): Show Ba/B ratings despite operational improvements (peer table, Q4 2023).

Rating Transitions: Drivers of Upgrades and Downgrades

Upgrade Triggers

Water utilities receive upgrades when:

• Multi-year DSCR improvement: DSCR consistently trending upward (e.g., 1.35x → 1.55x over 2 years) signals improving financial condition. Moody's, S&P, and Fitch all cite trends as driving upgrade decisions.
• Service area economic improvement: Population and employment growth accelerating beyond historical trends; new major employers locating in service area. Austin Water maintains Aa2 rating (Moody's) reflecting growth patterns, favorable demographics, and institutional presence supporting the system.
• Operational efficiency gains: Water loss reduction, O&M cost control, or capital project completion improving system performance.
• Management/governance changes: New CFO or board leadership introducing financial policies or planning approach. Management quality can support 1–2 notch upgrade if other metrics support.
• Debt reduction or refinancing benefit: Utilities paying down debt or refinancing at lower rates, reducing debt service burden and improving DSCR.

Downgrade Triggers

Downgrades occur when:

• Covenant violation or near-miss: DSCR falling below covenant minimum or within 10% of minimum. Downgrades often follow municipal bankruptcies (e.g., Detroit 2013–2015) and associated DSCR covenant stress.
• Multi-year DSCR deterioration: DSCR declining for 2+ consecutive years. Moody's 2022–2024 downgrade reports show that 85% of utilities with DSCR declining from 1.75x to 1.35x over 3 years faced downgrade pressure, even when current DSCR remained investment-grade.
• Rate covenant violation: Failure to maintain required DSCR despite rate increases; signals fundamental structural challenges.
• Cash flow deterioration: Days cash declining (e.g., 200 days → 90 days), signaling liquidity stress.
• Capital adequacy concerns: Deferring capital spending below 1.5% of revenue (Fitch 2024) correlates with downgrade risk; may lead to higher future costs per Fitch.
• Management or governance issues: Leadership changes, governance disputes, regulatory conflicts, or scandal can trigger negative outlook and eventual downgrade.
• Demand decline: Population or employment loss in service area; water consumption declining faster than rates increasing. Long-term structural demand decline is a downgrade driver.

Water Sector Credit Strengths and Resilience Factors

Water utilities maintain credit despite challenges:

• Service demand: Water demand is inelastic and essential; households cannot reduce water consumption below basic physiological needs. This underpins revenue stability.
• Regulatory framework: Rate-setting authority (independent from direct politics in most cases) permits rate adjustment to maintain covenants. Utilities maintaining DSCR above 1.20x reduced covenant breach risk to <5% in 2020–2023 (DWU analysis of 50 municipal water utilities).
• Long asset life: Utility assets (pipes, plants) have 50–100 year lifespans, permitting long debt tenors and matching of debt maturity to asset life.
• Bondholder forbearance: Bondholders pursued negotiated remediation in 92% of covenant violations (2018–2023 S&P data), with forbearance agreements allowing utilities to cure violations over 12–24 months.

Conclusion

Water and sewer utility credit analysis relies on a framework across the three rating agencies: S&P, Moody's, and Fitch all emphasize DSCR as the primary quantitative metric, supplemented by debt burden, cash reserves, system profile, and management quality. While methodologies differ slightly (S&P emphasizes infrastructure condition; Moody's emphasizes financial metrics; Fitch emphasizes water loss/efficiency), ratings map to financial metrics. DSCR above 1.50x, debt service below 30% of revenues, and days cash above 150 days are consistent with investment-grade (Baa+/A-) or higher ratings. Peer comparison is for understanding relative credit positions; utilities with metrics different from peers at the same rating level warrant investigation. Rating transitions (upgrades/downgrades) follow multi-year trends in DSCR, debt burden, or service area economics rather than single-year anomalies. Investors and analysts often monitor DSCR trends, cash position, and debt burden as leading indicators of credit stability and rating change risk (S&P 2023, Moody's 2022).

Disclaimer

This document was prepared by DWU Consulting LLC. It is provided for informational purposes only and does not constitute legal, financial, or investment advice. All data should be independently verified before use in any official capacity.