Rain Doesn't Cause Blocked Drains. It Reveals Them.
                     Outside Drains
Overflowing
After Rain?
What's causing it in West Sussex and how to stop it 
before the next downpour
WEST SUSSEX DRAINAGE GUIDE
Heavy Rain Exposes Hidden 
Problems
A minor issue in dry weather can become obvious in a storm.
Normal weather › Heavy rain › With a restriction
Water enters gradually A large volume of water The pipe can't move the 
and has time to flow hits the system in a short extra water, so it backs 
away. time. up.
Saturated ground makes it even harder for water to escape.
What Causes the Overflow?
Leaves & garden Soil & silt Grease & waste Tree roots in 
waste joints
Any one + 
heavy rain
Cracked or Poor surface Rain beyond = overflow
collapsed pipes drainage capacity
Debris, Soil & Silt Build Up
Twigs & 
Leaves Soil Debris
grass
Wet leaves stick and Collect against the Washes towards Rubbish restricts flow
cover grates grate drains in rain
H O W  S I L T  S L O W L Y  R E S T R I C T S  F L O W
1 2 3 4 5
Rainfall Soil moves Sediment enters Deposits settle Flow reduces
drain
Roots & West Sussex Conditions
Tree roots Local conditions
• Enter through cracks or damaged • Heavy rain adds pressure
joints • Saturated ground absorbs less
• Keep growing into a tougher • Some coastal areas drain slower
blockage
• Source: West Sussex County 
• Trap leaves, soil and debris
Council
• CCTV inspection can find them
Warning Signs to Watch For
Repeat problems in the same spot mean something needs checking.
Water drains unusually Water collects around one Unpleasant drain smells
slowly drain
Several nearby drains slow Water rises during rainfall Same area floods 
repeatedly
If a Drain Overflows: 5 Steps
01 02 03 04 05
Check the Clear loose Skip Watch the Book an 
surface debris chemicals water inspection
Look for leaves, Only what's They rarely fix See if it drains If it persists or 
mud or rubbish on visible and safe. deeper blockages once the rain returns, call a 
the opening. Don't reach in. and add risk. eases. professional.
Safety first: never force open a heavy or difficult drain cover.
Prevent It. Protect Your Home.
Keep leaves away from drain openings
Same drain keeps 
Clear visible garden debris regularly overflowing?
Keep grease and unsuitable waste out Get an expert inspection for 
blockages, roots, silt or damaged 
pipes.
Check drains after severe weather
Watch for repeated slow drainage
0333 577 0521
Book a professional check if it recurs Free quote • Precise Drainage Solutions