What is Portsmouth Water's GWSS score?

Portsmouth Water scores 88.9/100 on the Gera Water Service Score (GWSS) in 2024-25 — Excellent (grade A), ranking #3 of 19 UK water companies. The score combines leakage (90 l/p/d, weight 40%), supply interruptions (2 mins, weight 30%), and water quality CRI (0.45, weight 30%) from Ofwat APR 2024-25 and DWI data.

How much water does Portsmouth Water leak?

Portsmouth Water lost 90 litres of water per property per day through leaks in 2024-25, below the England and Wales average of 109 l/p/d. Source: Ofwat Annual Performance Report 2024-25, via DiscoverWater.co.uk (OGL v3.0).

How often does Portsmouth Water cause supply interruptions?

In 2024-25, Portsmouth Water customers experienced an average of 00:02:01 of lost water supply per property from interruptions lasting 3+ hours — better than the national average of 22 mins. Source: Ofwat APR 2024-25 via DiscoverWater.co.uk.

What is Portsmouth Water's Compliance Risk Index (CRI)?

Portsmouth Water's CRI in 2024 was 0.45, below the England and Wales average of 3.72. The CRI measures overall performance against national drinking water quality standards (lower = fewer compliance failures). Source: Drinking Water Inspectorate (DWI), Jan–Dec 2024, via DiscoverWater.co.uk.

How has Portsmouth Water's water quality changed over the past 4 years?

Portsmouth Water's CRI (Compliance Risk Index) over the past 4 years: 2024: 0.45, 2023: 1.24, 2022: 15.62, 2021: 0.45. Lower CRI = fewer quality compliance failures. Source: Drinking Water Inspectorate (DWI), via DiscoverWater.co.uk.

GeraMarket / UK water company performance / Portsmouth Water

Portsmouth Water: Performance Report

Rank #3 of 19 UK water companies · GWSS 88.9/100 (Excellent) · Leakage 90 l/p/d · Interruptions 00:02:01/property · CRI 0.45 (Ofwat APR 2024-25 / DWI 2024)

How does Portsmouth Water perform compared to other UK water companies?

In Ofwat APR 2024-25 / DWI 2024, Portsmouth Water ranks #3 of 19 UK water companies with a Gera Water Service Score (GWSS) of 88.9/100 — Excellent, 18.1 points above the national median of 70.8/100. Key metrics: leakage 90 l/p/d, supply interruptions 00:02:01/property, Compliance Risk Index 0.45 (Ofwat APR / DWI 2024, OGL v3.0).

Source:Ofwat APR 2024-25 + DWI CRI 2024 (via DiscoverWater.co.uk)·as of Ofwat APR 2024-25 / DWI 2024updated annually (last: 20 June 2026)

Gera Water Service Score88.9 / 100Portsmouth Water — Excellent (grade A) · #3 of 19 UK water companies · Ofwat APR 2024-25 / DWI 2024How this index is calculated

Reference period: Ofwat APR 2024-25 / DWI 2024· Ofwat APR 2024-25 + DWI CRI 2024 · Open Government Licence v3.0 · South East

Leakage score

75.2/100

90 l/p/d

E&W avg: 109

▼ below avg · weight 40%

Interruptions score

98.6/100

00:02:01

E&W avg: 22 mins

▼ below avg · weight 30%

Water quality score

95.9/100

CRI 0.45

E&W avg: 3.72

▼ below avg · weight 30%

Portsmouth Water performance figures (Ofwat APR 2024-25 / DWI 2024)

Portsmouth Water — Ofwat APR 2024-25 + DWI CRI 2024
Measure	Value	vs England & Wales
Gera Water Service Score (GWSS)	88.9/100	Excellent (grade A)
Overall rank	#3 of 19	vs national median GWSS 70.8/100
Leakage	90 l/p/d	▼ below E&W avg 109 l/p/d
Supply interruptions	00:02:01	▼ below E&W avg 22 mins
CRI (water quality)	0.45	▼ below E&W avg CRI 3.72
Region	South East	Ofwat regulatory area

Portsmouth Water CRI trend (2021–2024)

Compliance Risk Index (lower = better). Source: Drinking Water Inspectorate (DWI) via DiscoverWater.co.uk.

Year	CRI	vs E&W avg (3.72)
2024	0.45	▼ below avg
2023	1.24	▼ below avg
2022	15.62	▲ above avg
2021	0.45	▼ below avg

Compare Portsmouth Water with other water companies

Sort by GWSS, leakage, interruptions, or water quality to see how your company compares across all metrics.

Portsmouth WaterGWSS 88.9/100 · leakage 90 l/p/d · interruptions 00:02:01 · CRI 0.45

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Overall GWSS (highest first)

Company	GWSS	Leakage	Interruptions	CRI	Grade
#1SES Water	93.2/100	68 l/p/d	00:26:40	0.00	A
#2Bristol Water	89.7/100	68 l/p/d	00:06:49	2.84	A
#3Portsmouth Water	88.9/100	90 l/p/d	00:02:01	0.45	A
Leakage score 75.2/100 90 litres/property/day Interruptions score 98.6/100 00:02:01 per property Water quality score 95.9/100 CRI 0.45 CRI history (2021–2024, lower = better): 2024: 0.45 2023: 1.24 2022: 15.62 2021: 0.45 Full Portsmouth Water report →
#4Anglian Water	87.1/100	80 l/p/d	00:06:51	2.11	A
#5Affinity Water	84/100	95 l/p/d	00:03:21	1.44	B
#6South West Water	79.5/100	102 l/p/d	00:14:44	1.19	B
#7Wessex Water	77.9/100	108 l/p/d	00:10:00	1.31	B
#8South East Water	75.8/100	96 l/p/d	00:44:06	1.09	B
#9Cambridge Water	73.1/100	80 l/p/d	00:15:04	6.58	B
#10Yorkshire Water	70.8/100	111 l/p/d	00:08:27	3.61	B
#11Essex and Suffolk Water	69.4/100	64 l/p/d	00:04:40	10.94	C
#12South Staffs Water	64.3/100	103 l/p/d	00:15:04	6.58	C
#13Hafren Dyfrdwy	64.2/100	145 l/p/d	00:11:11	1.10	C
#14Thames Water	62.7/100	143 l/p/d	00:09:35	2.04	C
#15Severn Trent Water	58.2/100	98 l/p/d	00:04:34	10.32	C
#16Northumbrian Water	58/100	94 l/p/d	00:04:40	10.94	C
#17Southern Water	50/100	89 l/p/d	02:21:50	3.82	D
#18United Utilities	48.2/100	119 l/p/d	00:14:17	10.28	D
#19Dŵr Cymru Welsh Water	19.4/100	169 l/p/d	02:17:44	4.18	E

Showing 19 of 19 UK water companies. Source: Ofwat APR 2024-25 + DWI CRI 2024, via DiscoverWater.co.uk (OGL v3.0).

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Frequently asked questions

What is Portsmouth Water's GWSS score?: Portsmouth Water scores 88.9/100 on the Gera Water Service Score (GWSS) in 2024-25 — Excellent (grade A), ranking #3 of 19 UK water companies. The score combines leakage (90 l/p/d, weight 40%), supply interruptions (2 mins, weight 30%), and water quality CRI (0.45, weight 30%) from Ofwat APR 2024-25 and DWI data.
How much water does Portsmouth Water leak?: Portsmouth Water lost 90 litres of water per property per day through leaks in 2024-25, below the England and Wales average of 109 l/p/d. Source: Ofwat Annual Performance Report 2024-25, via DiscoverWater.co.uk (OGL v3.0).
How often does Portsmouth Water cause supply interruptions?: In 2024-25, Portsmouth Water customers experienced an average of 00:02:01 of lost water supply per property from interruptions lasting 3+ hours — better than the national average of 22 mins. Source: Ofwat APR 2024-25 via DiscoverWater.co.uk.
What is Portsmouth Water's Compliance Risk Index (CRI)?: Portsmouth Water's CRI in 2024 was 0.45, below the England and Wales average of 3.72. The CRI measures overall performance against national drinking water quality standards (lower = fewer compliance failures). Source: Drinking Water Inspectorate (DWI), Jan–Dec 2024, via DiscoverWater.co.uk.
How has Portsmouth Water's water quality changed over the past 4 years?: Portsmouth Water's CRI (Compliance Risk Index) over the past 4 years: 2024: 0.45, 2023: 1.24, 2022: 15.62, 2021: 0.45. Lower CRI = fewer quality compliance failures. Source: Drinking Water Inspectorate (DWI), via DiscoverWater.co.uk.

Other South East water companies

Contains public sector information published by Ofwat / Drinking Water Inspectorate and licensed under the Open Government Licence v3.0. Source: Ofwat APR 2024-25 + DWI CRI 2024 (via DiscoverWater.co.uk) (Ofwat APR 2024-25 / DWI 2024, published June 2026 (Ofwat APR 2024-25)).