Slope and Runoff Questions Checklist

Go out during steady rain rather than only afterwards, and note the points where water crosses onto your ground instead of the places it eventually settles.

Entry points are visible only while water is moving, so a garden looked at once the rain has stopped shows where the trouble ends but never where it starts.

Write down what lies immediately uphill of your boundary, whether that is a road, a field, a yard, a track or another garden.

A professional will want to know what this plot sits below before taking any view on why water is arriving at all.

Walk the uphill boundary looking for gaps, low points, gate thresholds and washed hollows where water has clearly been passing through.

Water leaves marks wherever it crosses a line, and those marks stay legible long after the ground itself has dried out.

Note which roofs, drives and yards near you shed water in your direction, keeping to what you can see rather than assuming where their pipework leads.

What is visible from your side is an observation; what happens underground next door is not, and confusing the two weakens the whole record.

Where any roof or paved area actually discharges is for a qualified drainage professional to establish, and it cannot be inferred from the surface.

Record where silt, grit, bark or leaf litter has been left in fans or lines, since deposits mark the places where arriving water slowed down.

Sediment is a record of flow that nobody had to be present to witness, and it generally points back towards the source.

Write down anything a neighbour has said about water arriving on their own land, and label it clearly as their account rather than as your observation.

Neighbour recollection is a useful lead for a professional, but it misleads the moment it is quietly mixed in with what you saw yourself.

Walk the plot and mark on a sketch which areas read as high and which read as low, describing them relative to one another rather than in figures.

Relative description is genuinely useful to a professional and cannot be wrong in the way an owner measurement so easily can.

Note where the slope flattens out, because the change from falling ground to level ground is usually where water stops moving and starts to stand.

The break of slope explains far more standing water than the low corner everybody looks at first.

Record every hollow and dished area, including shallow ones that only become obvious when they are holding water after heavy rain.

Shallow dishing is invisible in dry weather, so the wet spell is the only chance to map it accurately.

Note anything lying across the slope that could hold water back, such as a raised path edge, a kerb, a step, a wall or a dense hedge line.

Barriers across a slope pond water on their uphill side, which explains a great many wet patches that appear to have no source at all.

Note whether the ground beside the building reads as higher or lower than the garden around it, and record it without drawing any conclusion.

This is one of the first things a professional will look at, and an owner note made before anything is disturbed is genuinely valuable.

Ground levels against a building affect the fabric of the property and must be assessed by a qualified professional before anything is altered.

Photograph the slope from a few fixed positions you can return to, so that later pictures can be compared directly with these ones.

Comparable photographs are worth far more than a larger number taken from wherever you happened to be standing at the time.

Follow the moving water from where it enters to where it stops, and draw that route on your sketch as a line rather than shading a general area.

A line can be checked, questioned and walked again, whereas a shaded area tells the next person almost nothing.

Look for flattened grass, combed leaf litter and scoured soil, all of which mark the route water took when nobody was there to watch it.

These traces let you reconstruct an event you missed, which matters because the heaviest rain rarely falls while you are watching.

Note where the route splits or changes direction, and what appears to cause it, such as a mound of spoil, a bed edge or a change of surface.

Every division in the route is a place where a small feature is doing something significant, and those features are easy to remove by accident.

Record where the route crosses a path, a step, a threshold or a doorway, since these are the points where runoff stops being merely interesting.

Crossing points are where an owner notices the problem, and they are what a professional will want to see first.

Water reaching a threshold or a doorway should be put to a qualified professional promptly rather than watched through another wet spell.

Compare the route after different rainfall events and note whether it repeats exactly, shifts sideways or only appears when the rain is heavy.

A repeating route points at the shape of the ground, while one that appears only in heavy rain points at something being overwhelmed.

Describe how the water behaves in ordinary words such as trickling, sheeting or running in a channel, without attempting to put numbers to it.

Plain description survives scrutiny, while owner estimates of volume or speed rarely do and can send the whole conversation off course.

Mark every place where water stands and date each observation, so the record shows a pattern rather than one memorable wet afternoon.

A single dated note is an anecdote; several of them across different rainfall become evidence somebody can act on.

Note how long standing water took to clear in your own terms, such as gone by the following morning or still sitting there the next time you looked.

Comparative persistence between one area and another is the useful part, and it means nothing at all without the date attached to it.

Record what the standing water actually reaches, such as a wall, a shed base, a fence post, a step, a stored item or a planted bed.

What gets wet decides how urgent this is, and it is the detail most often left out of an otherwise careful description.

Where water reaches a building, an outbuilding or anything electrical, stop observing and put it to a qualified professional.

Separate the places that hold water every time from those that held it once, because the two lead to completely different conversations.

One exceptional event tells you about the weather, whereas a repeating pattern tells you about the ground and what has been done to it.

Describe depth against something familiar that appears in the photograph, such as the edge of a slab or the base of a post, rather than giving a figure.

A picture of water with nothing recognisable beside it is almost impossible for anybody to interpret once the water has gone.

Note the parts of the plot that never hold water at all, since the dry ground helps a professional make sense of the wet ground.

Contrast within one plot is far more informative than a general statement that the garden is wet.

List the paved, compacted and covered areas on your own plot, and note roughly which way each of them appears to shed water.

Starting with your own ground keeps the record credible before anything is said about anybody else.

Note where grass or bare soil has been compacted by parking, storage or constant traffic, since compacted ground can shed water much as paving does.

Owners account for the paving and overlook the worn ground beside it, which may be behaving in a very similar way.

Record any surfacing, decking, building or hard standing that has appeared on adjoining land, together with roughly when you noticed it.

Timing is the whole value of this note, and it is lost within a surprisingly short while if nobody writes it down.

Whether work on adjoining land altered how water reaches you is for a qualified professional to assess and, for responsibility, the relevant authority.

Note whether loose material such as gravel, chippings or bark washes downhill during rain, and where it comes to rest afterwards.

Material on the move shows both the strength of the flow and the point at which it slows, and it can be read the morning after.

Check whether membrane, sheeting or an old covered base is showing anywhere at the surface, and record its position without disturbing it.

Buried coverings change how water and roots move, and their extent is rarely known to anybody currently living there.

What lies beneath a covered surface, and how it affects water, is for a qualified professional to establish on site.

Note the roofs on your own plot, including sheds, garages, canopies and lean-tos, and where the water leaving each of them lands.

Small roofs are regularly left out of the account even when their water lands squarely on the wettest part of the garden.

Write down when you first noticed water behaving this way, and what was happening on or near the site around that same period.

The moment something changed is the single most valuable thing an owner holds, and it is rarely written down until it is needed.

List works carried out on your own plot, including landscaping, extensions, resurfacing and any ground that was built up or taken away.

A professional reads this list looking for the point at which the ground stopped behaving as it used to.

Note works you are aware of on neighbouring land or in the road, keeping strictly to what you saw rather than what you believe it did.

Observation of nearby work is fair to record, while any conclusion about its effect is for others to reach on proper evidence.

Whether nearby work altered how water reaches your plot is for a qualified professional and, where responsibility arises, the relevant authority.

Record any tree, hedge or large shrub that has been removed and where it stood, since established planting takes up a great deal of water.

Removal is often followed by a change in how wet the ground is, and the connection is easy to miss once the stump has gone.

Note anywhere the ground level has been raised or lowered, including spoil spread from other works and beds that have been built up gradually.

Beds raised a little at a time can end up acting as a barrier across a slope without anyone ever deciding to build one.

Distinguish behaviour that appears only during long wet spells from behaviour that is now present whatever the weather has been doing.

That distinction often decides whether the conversation is about surface water at all, and only somebody living there can make it.

Put every entry point, route and standing area onto a single marked sketch rather than spreading them across separate notes and photographs.

One drawing lets somebody see the whole pattern at once, which is exactly what scattered notes prevent.

Keep photographs dated and grouped by rainfall event, so that the same place can be seen under different conditions side by side.

Grouping by event turns a folder of pictures into a comparison, which is where the meaning actually lies.

Note whether each observation followed light rain, a heavy downpour or a long wet spell, described in ordinary terms rather than measured.

The same ground reads as free draining after light rain and as hopeless after a long wet spell, so context decides what an observation means.

Ask a qualified drainage professional what they need from you before runoff can be discussed properly, and write the answer against your notes.

Finding out what is missing early avoids losing another wet spell to a gap that nobody thought to mention.

Keep your own theories about the cause on a separate page from your observations, clearly labelled, so the evidence is not coloured by them.

Owner theories are often close to right and occasionally badly wrong, and mixing them in makes the good observations harder to trust.

Set down your questions about responsibility and about any connection separately, and put them to the relevant authority or drainage undertaker.

Sorting the questions by who can actually answer them saves a great deal of time and stops the wrong person being asked.

Responsibility for water crossing land, and any question of connecting to a drain, rests with the relevant authority or drainage undertaker.