HHSRS VERSION 2

SEPTEMBER 2004

CONTAMINATION

All ages

None

WATER

Vulnerable age

Related hazards

Ultra-violet filter

HHSRS VERSION 2

Multiple locations

Yes

No

Secondary hazards

Yes

No

Settlment tanks near stream

DESCRIPTION OF HAZARDS

Holiday house

Reservoir on stream

Detached second homes built in 1970s

A)

LIST OF RELEVANT MATTERS

LIKELIHOOD & OUTCOMES

A

# Secondary hazards

A

a

Water supply tap

-

-

None

-

b

Intermittent supply

-

c

Water pressure

-

d

Water temperature

-

e

Defective pipework etc

-

Key

3

Seriously defective

f

Contamination of tanks

-

2

Defective

g

Water filter defects

3

1

Not satisfactory

h

Water softening system

-

-

Satisfactory/NA

Dwelling:

Background: The house, which is used as a second home, is situated in remote woodland in a

mountainous area. It is on mains electricity, but has its own private water supply.

Private water supply:- All water to the house comes from a mountain stream running through the

grounds, which has been dammed to produce a small shallow reservoir. From an inlet pipe near the

dam, the water first runs a short distance to a sunken settlement tank adjacent to the steam, which

has three chambers. After passing through these chambers, the water is piped underground to a

small pump room adjacent to the house. Here it is pumped through an ultra violet filter and up to a

storage tank in the roof of the house. This supplies the kitchen tap, other cold taps, the w.c. and a

hot water cylinder.

Rodents have chewed through a loose cable in the pump room thereby disabling the operation of the

u.v. filter, but leaving the pump to still operate.

HHSRS VERSION 2

SEPTEMBER 2004

HEALTH AND SAFETY RATING SYSTEM SCORES

1946-79 House

1 in

3

LIKELIHOOD

Low

High

Average: 1,700,211

Example

3

< 4200 2400 1300 750 420 240 130

75

42

24

13

7.5

4

2.5

1.5 >

Justification

OUTCOMES

Class I

Class II

Class III

Class IV

Justification

RATING

As the supply is taken from the stream several miles from its mountain source, it is

heavily contaminated by both solid particles and microbiological organisms. While the

initial settling beds filter out the solid matter in the stream water, the system relies on the

ultra-violet filter to eradicate the microbiological contamination.

With this filter out of

action, contaminated water is being pumped into the storage tanks and fed to the kitchen

and other cold taps. The likelihood of drinking this water and being infected by it is very

high.

%

Average: 0.0

0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 1.0

1.0

0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 9.0

10.0

0.15 0.3

0.7

1.5

3

7

15

26

38 >

Av: 90.0

89.0

0.0

1.0

10.0

89.0

0.0

< 0.05

< 0.05

< 0.05

< 0.05

Although

average.

0.15 0.3

0.7

1.5

3

7

15

26

38 >

the likelihood of infection is very high, the spread of health outcomes is

Average: <1

I

J

Example

A B C D E F G H

1630

Score

RATING SCORES AFTER IMPROVEMENT

IMPROVE

Justification

NEW RATING

Av: Nos

Likelihood to

1 in 320

Outcomes to

0.0

1.0 10.0 89.0 %

Although representing a serious hazard in its present state, restoring the water system to

provide potable water would be very quick and inexpensive. All that is required is for the

cable to the ultra-violet water filter to be replaced and the pump room to be sealed or the

cabling placed in a metal conduit to prevent further attack by rodents. However, due to

the nature of the supply and system, some risk is likely to remain.

Improved

A B C D E F G H

I

15

Average likelihood, outcomes and HHSRS score for hazards from contaminated water for

all persons in 1946-79 dwellings not in multiple occupation, 1997-99

Score

Av: <1

J